I’m pretty sure mine is due to the “O” rings in the 4 position Anderson Valve at the inlet panel. Apparently you’re not supposed to turn that valve while there is incoming water pressure. I’ve looked at the replacement modules for that valve and they look like you could have some blow by if the “O” rings get dislodged. On the good side it is intermittent. I think if you rotate the dial on the valve past the setting you want it on then back it may help keep the “O”rings seated.
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