Thank you @ajeshm!
I was able to downgrade my C8 to 2.3.4.148.
Both sensors SNZB-02 and SNZB-03 were added and initialized quickly without any problems. It's not latest version and maybe I'll hit to other bugs or limitations, but at least I can play around while waiting for latest version fixes.
You made my day! Thanks again. 
2,3.5.118 worked for pairing new device for me too.. as u .123 did not.. stuck on initializing
It seems that issues are different for many people. I have several Hue Gen1 motion sensors and one Gen2 sensor. They are all working just fine with the C8.
It seems there are variations in the Aqara devices. Your contact sensors are working. My leak sensor and vibration sensor did not work on earlier C8 firmware; I have not tried adding them since updating to the most recent update.
Just purchased and flashed a pair of these and put them into my Hubitat Zigbee mesh to test. Will watch my Zigbee routing to see what they do. The stats look good on them. Curious if the coordinator will put them to use. My Zigbee mesh seems to have settled though - haven't been dropping any devices lately even without these. Pairing is still sometimes janky.
Today I saw there is new version available (2.3.5.124). After upgrading C8 to the latest version I was able to add/initialize 3 new sensors (SNZB-04) without any issues. SNZB-02 and SNZB-03 also works OK.
+1. Similar issues with Sengled devices.
I'm having this sand issue with my C7 and 2 new aqara contact sensors that i bought while reduced for Prime day. I have 3 of the same model sensor that have been connected for months. One of these drops off occasionally and reconnects without issue.
I also got an Aeotec extender since these are going to be relatively far from my C7 and the older sensor that drops off occasionally is the further from my hub.
Anyone else having there issues with the C7? The legacy pairing mode isn't available in the C7.
Thanks!
I have a couple of aeotec 6's still plugged in and they run fine.
I never had issues pairing Aqara contact sensors w/my C7. Have you tried rebooting your hub?
The sensors that have been connected in the past are still connected but when i try to add new ones, they get stuck at initializing like others experienced earlier per the OP.
I have rebooted the hub and it didn't help.
Odd - I just joined an Aqara contact sensor to my C7, didn't have any issues. It wasn't particularly close to the C7, connected via a SonOff USB Dongle P repeater (Zigbee 3.0).
Is there a way to tell if a device is trying to connect thru a bridging device instead of directly to the C7?
As mentioned, i just got an Aeotec zigbee extender; after connecting it to the C7, I put it between me and the C7 and tried to connect the new sensors and got the same result as when trying to connect directly to the C7.
Unfortunately it's impossible to tell (unless you're directly sniffing network traffic) how the device is joining/trying to join, even w/a repeater between the device and the hub. I frequently find "wacky" connection paths in my house, w/devices connecting to repeaters in rooms on the other side of the hub, that then connects back across the house to the hub. Strange but true... 
Not sure why you're having problems w/the Aqara...staying connected has been an issue w/Aqara for a while, getting connected wasn't an issue I remember seeing.
What model? I only know of Aeotec having z-wave ones? When did that change? The zistick isn't a repeater as far as I know. It's only a controller.
Yeah I just found it...
Jeff
Unless you get Aqara devices that are Zigbee 3.0 certified, they may not work with Hubitat. The Aqara devices MIGHT work with the C7 depending upon the repeaters you have in your Zigbee mesh.
I purchase an Aqara leak detector and vibration sensor for use with my C7. I could not get them to connect and stay connected until I replaced four older smartplugs I had in my mesh. The cost of the new smartplug/repeaters was more than the cost of the Aqara sensors. When I upgraded to C8, the Aqara devices stopped working. Rather than continuing to mess with them, I decided to replace them with Zigbee 3.0 certified devices from other manufacturers.
IMHO, Aqara devices are just not worth the hassle even if you save a few bucks. Now if Aqara starts to sell devices that are Zigbee 3.0 compliant, they might become useful.
I have three of this same model Aqara contact sensors that I've had in use since last October connected directly to the C7 with no issues other than one dropping off occasionally. The newer community driver has a presence flag so i get a notification when that one drops off; it sometimes reconnects on its own but i usually have to force it reconnect.
The one that drops is the furthest one from the hub - that's why i got the extender for the two new ones that will be further away in the same direction.
This was similar to my experience w/the C7 & Aqara contact sensors last year...I had one that dropped a couple times and came right back, but overall they were very stable. Others have had success w/them but there definitely have been problems reported keeping the Aqara sensors on Hubitat, it's been a common issue, and one that caused me to give up on Aqara sensors about 1 1/2 years ago when they just would not stay on my hub (C7). Biggest change to my Zigbee mesh is probably my addition of several SonOff USB Dongle P repeaters...not all the aqara connect through them, but that's the only major change to my mesh between when they didn't work and when they started working, aside from various hub FW udpates.
Like I said previously, I don't remember people reporting having problems getting the Aqara sensors to join the hub, just problems keeping them on once joined. So this seems new/different issue to me. Have you tried removing the battery from the sensor, waiting a couple minutes and then re-inserting the battery and resetting the sensor to try to join it again?
Download the Hubitat app
