Thank you for your feedback. I have also reached the team of the plugin Modern Events Calendar (MEC). They confirm that incompatibility. Please find below their answer :
“Thanks for reaching out.
Unfortunately, we don’t have compatibility with your third-party plugin.
You can ask the developer of that plugin to contact us so we can cooperate and provide a compatible version for future updates.
In the meantime, I’ve forwarded this ticket to our developer team, and it will be checked and fixed for the next updates. But we don’t have ETA for when this issue will be fixed.
Have a wonderful day.
I have made some tests with and without your plugin, and i have registered the wordpress logs and screenshot for each of the tests.How can i send to you these logs files and screenshots?