Not from our end, I don't think? Per others, it appears that guest sessions are no longer a thing in recent versions of Ubuntu. And as for other flavours and/or derivatives, per Olivier's comment shouldn't this issue be directed/tracked there if its cause is outside Firefox?
Bug 1757195 Comment 10 Edit History
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Not from our end, I don't think? Per others, it appears that guest sessions are no longer a thing in recent versions of Ubuntu. And as for other flavours and/or derivatives, per Olivier's comment if the cause of this issue is outside Firefox, shouldn't it be directed/tracked there in the appropriate upstream?