From few day "Invalid traffic - Could not associate packet to any connection"

I've been detecting a strange behavior on an xgs 2300 (SFOS 19.0.1 MR-1-Build365) for a few days.
At first the connections of some PCs to an IP seem to work but then I start to log a series of errors such as "Invalid traffic" (I attach a screenshot). The firewall rule is a simple LAN to Wan rule without any checks (only audio streaming checks). Other PCs, on the other hand, access easily. The destination IP is from a banking institution and with this firewall configuration it has never had reachability problems. Can I investigate what?

Added TAGs
[edited by: emmosophos at 7:55 PM (GMT -8) on 24 Jan 2023]