This sounds silly but i had a similar issue occur with an HP OfficeJet 8600 wireless printer for one my clients. The printer would associate just fine. Then about five minutes later dis-associate and keep attempting. According to some documentation i found, this particular printer does not like connecting to multiple AP environments that broadcast the same SSID. So I ended up creating a separate SSID for this printer and assigned that SSID to the Meraki AP closest to the printer. It's worked well so far. Just throwing it out there as the errors your having were similar.
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