Sounds like maybe there is a bug in the D5 Next RGBpx firmware or maybe in AQS. Hopefully someone from Aquacomputer will chime in here about this. My experience has been that they are pretty good at fixing bugs once you convince them that it is a bug and not user error. I have found several obscure bugs in AQS. Once I was able to replicate the problems, and more importantly, they were able to replicate the problems, they fixed them in the next release of AQS. This sounds like a problem that comes and goes. I have had those too. I import data from HWINFO through shared memory support. I have had certain sensors just stop reporting in AQS. The author of HWINFO gave me a utility that shows what the shared memory is reporting. The sensors that stop reporting show up normally in the shared memory viewer utility but not in AQS. I have to select the item, then Change Data Source, then reselect the sensor value that dropped out. Then they work again. This only happens now and then. I also spent 2 weeks fighting with auto-load of an overview panel. I would select an overview panel to auto-load and it just would not work. I could see the panel ID being updated in the config XML file but the overview panel would not auto-load when AQS starts. I tried everything I could think of to fix it and got nowhere. Then a few days ago it just started working again even though I had not changed anything.
These are tough bugs to prove to Aquacomputer because they are not consistent. What you guys are seeing sounds similar. If you can figure out how to reproduce the problem consistently, then post your setup and procedure here, if they see it they will (hopefully) try to replicate the problem. If they do, they will fix it. Good luck!