My wife's old Toshiba laptop (Toshibas are complete and total garbage on so many levels) had both a burnt out Wifi NIC and Sound Chip that would overheat. Toshiba refused to recognize the issue even though tens of thousands were affected across multiple product lines. (Obviously trying to avoid angry customers and warranty claims on bad motherboards) Everyone I personally knew with a Toshiba had a dead NIC within two years.
Any way, the wireless NIC (WiFi) would appear in the status bar, but it would just refuse any traffic. The radios burnt out on the 2.4GHz channel. (It was just a poor design) So that is also a possibility.
My Linksys AC2600 (Also a garbage brand now) did the same thing. It would work. Then traffic would drop, connection would go away, and then reappear. Again it was, burnt out radio chips.