This isn't directly hubitat related, but I know the members here are quite knowledgeable on related topics, so I thought I'd try.
I just installed some Sengled bulbs with a candelabra base in the ceiling fan* in my son's room. I had no trouble connecting them to my Hue hub, with them flashing when first detected and then dimming as they were added. Now that they're connected, I can dim them fine from the Hue app (from 1-100%), but they don't turn off when I switch them off in the app. They stay at the same brightness as before, as if they never received the command at all.
Any idea what would cause this?
*I see on sengled's site that their bulbs are 'not meant to be used' in ceiling fan fixtures. I'm not sure why that would be, but that's never been a problem for me before with their A19 style zigbee bulbs.
I wasn't aware that any Sengled bulbs could be joined to a Hue Bridge network at all, though I've seen that their newer bulbs are Zigbee 3.0 (according to certification docs I've seen; I've never owned one myself), and a Hue Bridge update as of at least a couple years ago was supposed to enable Zigbee 3.0 compatibility for such bulbs. So, I suppose that is theoretically possible now--just not something you'll find a lot of people here having done, at least not yet.
That being said, I don't really have any ideas. I assume it's all such bulbs and not just one? You could try resetting the bulb and re-pairing it to the Hue network to see if that helps. Otherwise, I'm not sure, other than that Hue doesn't guarantee compatibility, though they'll let any bulb pair (they did try a allowlisting only certain bulbs, I think all their own, a while back via a Bridge firmware update and quickly reverted after backlash). So, it's possible these are doing something unusual and simply won't work. Since you have Hubitat, you could try directly pairing them to the hub, though I don't blame you for wanting to use them on a Hue network if at all possible.
I can confirm that Zigbee 3 bulbs do work on the Hue I just got through testing some really inexpensive ones called "Liokkie".. These do turn on/off and even restore state after a power loss on both HE and Hue...
Now you've got me thinking... This is in a new house, setting everything up fresh. I thought the sengled bulbs at my old house were connected to the Hue hub, but maybe not? I know I had non-hue bulbs connected through the hue hub, including IKEA Tradfri bulbs, but the Sengled bulbs specifically I can't say for sure. No internet at the old house right now, so I'll have to check when I go back over there next.
I bought 6 of these sengled candelabra bulbs, and installed them in 2 ceiling fans. They are all exhibiting the same behavior. I did confirm that the box shows Zigbee 3.0. I do vaguely remember though something about ZHA vs ZLL for Hue compatibility, was that pre 3.0, or is that still a thing?
Sengled works great with HE, at least the color+ A19s and BR 30s I am using do.