Error in ESPO Logfile

[pehoma]

Hello together.
Since a few days we have some problems with ESPO. We get from time to time a 500 error or also 502. So I am checking the Logs.
Within the log file I found this:
[2023-08-14 07:16:13] WARNING: E_WARNING: foreach() argument must be of type array|object, null given {"code":2,"message":"foreach() argument must be of type array|object, null given","file":"/var/www/vhosts/pehoma.com/espo.pehoma.com/custom/Espo/Modules/Advanced/Core/Workflow/Actions/UpdateRelatedEntity.php","line":32}

We haven't changed anything so what cause this error?

Thanks in advance for your help

[shalmaxb]

I had something like this in a field, which was mandatory and had no value in a record. And when saving another linked record, this field was not filled, this kind of error occurred.