Solved

17/16

When I was scrolling through a league, I found an Elite league which is overcapacity (17/16). This should not happen and something is wrong.

This is the league with the error:
League not found or inactive

Additional comments:
This league is not my league nor this report is my explorations so credits to https://igpmanager.com/app/d=profile&user=2030567&tab=overview for first exploring this bugs

Hello,

This isn’t a big issue, sometimes a member joins a league in the same time that promotions or elegations happen. The system itself will fix it in the next season by promoting or relegations more/less managers than usual.

It's a old bug that practically works like this: if you enter a championship at the last race and you have already done your daily race (one every 24h), the system does not consider you a participant of the championship and does not demote you  because you didn't do any races in that league, so leave you there.  Then normally there is a relegation and the 2 promotions, plus you who remained there, become 17. Also work for 18.