Hi Guylaine
Investigating this issue further, we have a couple of potential leads: (a) administrator groups relied on a now discarded regex rule; (b) the administrator rules broke following (or as a result of) the new SSO; or (c) invalid administrator rules were migrated but fails parsing. I appreciate that this information might not be terribly useful for you, but please rest assured that we are trying a number of different things as we chase this down.
I hope to be able to give you an update later today.
We appreciate your continued patience!
Thanks!