Well, as mentioned before, I was able to both “see” and “connect” to an open (unencrypted) network in Airplane mode with FP3, so whatever steps are required to reproduce this bug, Airplane mode isn’t all. Either not all phones are affected, or additional side conditions need to be present such as specific Wifi modes or channels used. (802.11b, g, n, a, c x … localization/area restricted channels such as 12 & 13 etc)
there are other threads that suggest FP3 has issues with some combinations, especially in the 5GHz band, sometimes in combo with weak signals…
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as such its possible that this is only a small part of a larger wifi issue which you triggered by chance.