Just had a support call with apple on this
they are aware of the problem and have escalated it to investigate and fix
they had me do two things that MAY have resolved this permanently for some people
1 go to setting general , go to the bottom select reset, select reset all settings
i was a bit nervous but they assured no data would be lost
lost some minor config like walpaper Wi-fi password etc but rest all good
it restored the iPad dock but a reset is the same as turning on and off however support chap says this MAY fix it permanently
this is not a thing to do repeatedly but just the once to see if it resets the bug permanently
2 he suggested I swipe up and get the control panel and switch the lock rotate on and off
i think the idea was that if it happens again to try this to see if it fixes problem
wish we had tried this first🙈😑
my apple fault will remain open and I will continue to play angry birds 2 which seems to cause the problem quite frequently and report back to apple if problem recurs
i mentioned quite a few people have reported on the forum had not seen much apple interaction so far
he assures me it’s on their internal forum and is being actively investigated by apple
hopefully we will see a firmware update soon👍-1F3FB;😏
good luck