Fields loosing property 'readonly' after a while

[fxp66]

I have the issue that fields, which are set to 'readonly' property are loosing this after a while, without any changes or cacheclearing. Is this a misconfiguration, or a bug?

best regards
fxp

[mpruy]

I have the same problem, losing values of a custom field in the frontend. Clearing cache solving the problem for undefined time.
Using TYPO3 12 with EAP-Version of Powermail.

Are there any known issues about that?