VanEE HRV running on max even when set to low/intermittent

[HRVnewbie]

We have a VanEE HRV 60H in our apartment, which I always have set to "intermittent". We recently returned from vacation and found the unit blinking and had to have the motorized damper replaced. It's been working fine for the past two weeks since but last night when it switched on, I noticed it was louder than usual, as loud as it would be if set to "max" instead. I tried switching it from "intermittent" to "min" or "max" but it made no difference. It still switched off though, but when I switched it back on, it was still louder than usual until the second time i switched it off and on again. At that point, it was the usual noise level at the "min" setting and off at the "intermittent" setting. I left it at "intermittent" and went to bed. When I woke up this morning it was running loudly again. Any idea what might be causing this? Thank you!