Thread updated with more info here:
https://forum.topeleven.com/bugs-tec...tml#post653971
Taken from that thread:
Due to the training issue following season update, we’re reverting all player quality gained from this period during which the issue was occurring. Any quality gained following the patch being pushed has not been affected.
This is to ensure fairness across all competitions for the season for all clubs. For any further followup, please get in touch with our Support via the “?” in-game as they will be able to provide details.
This will require ~10 minutes of offline time which will begin shortly. We will provide updates when it has begun/ended in this thread.
Once again, many apologies for the inconvenience and thank you for your patience.