Hi, I can confirm the problem using the File > Examples > WiFiNINA > AP_SimpleWebServer example sketch with a channel argument added to WiFi.beginAP(). Even with the beta version of the WiFiNINA library and the beta version (1.2.4) of the NINA firmware, the problem still occurs on my Uno WiFi Rev2. I also tried it on my MKR Vidor 4000 and had the same problem.
It does seem like a bug with the WiFiNINA library. I did a search and found that this bug has not yet been reported to the Arduino developers. Would you care to file a bug report in the WiFiNINA repository? You can do it here: