If I read your setup correctly. The Optex has an output that is triggering a PSC01 Powerflash module.
It is sending a power line signal to an appliance module and a chime module. When the alarm is triggered on a zone violation.
The chime module seemed to be working in a selected location then getting intermittent and the siren connected to the appliance module will not shut off.
Any added data you can provide will be a help. Like the Powerflash is triggered by a voltage or dry contact. Siren is a 120 volt or one driven by a low voltage power supply?
Do you know if the appliance module maybe turning Off and then right back On again?
Since you had to find a location for the chime module that worked. You may have a power line signal problem to the appliance module and it is not turning off. Power line signal could also be changing to the chime module.
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