I've the same problem, and have had the issue for a year.   I escalated the issue to TPG support but to be honest they were not much help.   Tried switching off band steering and using separate channels for 5/2.4 ghz but found this made the issue worse.   I've given up and was thinking of switching from TPG but have purchased a different router from amazon.   TPG really should acknowledge this issue and consider using different hardware. ... View more