SuiteCRM 8.2.3 many-to-many relationships: new entries not linked if created through subpanel

Hi guys!

I have a custom Experts module created via the Module Builder and based on the “person” module type. It has a many-to-many relationship to the Contacts module, both modules have corresponding sub-panels. If I use Action → Create in the sub-panel, then a new Expert is created, but not linked with the corresponding entry in the Contacts module (this works the same way in the opposite direction, if you create a new Contact from the sub-panel on Experts module - a Contact will also be created but not associated with the Expert).

Judging by my findings, this problem happens specifically with the Contacts module, I created many variations of custom modules and the problem is always exactly the same, I also installed a clean version of SuiteCRM 8.2.3 and this problem is also present there.

Standard modules with many-to-many relationships to Contacts (eg Documents, Projects etc.) work fine. Also studying suitecrm.log (level: debug) I noticed that a SQL query is being executed to create an entry (for example in the Experts module), but the SQL that should insert the entry into the connection table (contacts_gc_experts_1_c) is missing in the logs.

I’d be grateful for any help!