Interesting, at least it's not related to the sensor but something during pairing.
Maybe that's because now I've paired it over a Tradfri outlet repeater instead other ones were directly to the hub?
Seems anyway that it's still working properly, it's just a minor graphic issue.
But as @mike.maxwell suggested can you check the version number? I just did a more detailed look into your screenshot and my errors although similar were not as yours, mine often would leave fields blank or truncated
The only issue that could arise is that the correct device driver isn't chosen when the sensor is paired. The model / manufacturer data isn't used in any other ways for the door/window contact sensors or the leak sensors.
I believe what happens is that during the pairing process the value telling the hub the length the model text string is missed somehow, so extra "garbage" characters are picked up as part of the model name.
As other have suggested, you could try repairing the sensor if the "garbage" characters really really bother you, but nothing is "broken". The devices for the above screenshots have been connected and working just fine with my hub for over 8 months now.
Not sure what is 'normal', but the one temp/humidity sensor I've paired so far has checked in ~20 times in the last hour... Actually 62 times, but each time it checks in there seem to be 3 Checkin events in the log within ~1 second.