@RodrigoSQL 

Hi, thanks for posting question here.

Sorry to hear you issue. Did you ever take factory reset or downgrade to the previous official firmware manually (same as upgrade)? You may have a try then check whether the same issue remains.

  @Marvin_S 

Hello, yes, this has already been done, it is a problem at the firmware level, what is scary is the lack of support from TP LINK, there are some posts here on the forum about this problem, the ONLY way to solve it is by using this old update from years ago BETA, because all the others including the last one mentioned here have the same problem, it is a high-value router and this disregard for the customer makes me seriously rethink whether I will ever buy a TP LINK router again... it is a huge disregard, I have been following this problem for over 2 years... regrettable.

Understand the brand's desire to resolve the issue, they don't care about the chronic problem reported, if you are thinking about a router, stay away from TP-LINK. This disregard for the customer in an expensive piece of equipment is unacceptable.