404 - file not found for file: reload/

Hi all, After an upgrade to 8.15.2 I see this error popup every few seconds in the console. While I usually figure this out easily I do not have a clue where this is coming from. Searched through alle widgets/files but I cannot find this.  Anyone has an idea where to look or what is causing this? Logging to trace shows this:   Connectors: Request: reload/ split into: handler: reload/ and pathRemainder:     
1 answers

The http requests option (under displayed log sources) may give you some more clues about where the request is coming from. In Mendix Java implementations of request handler should be present if this was functionally working before.