Since the 'is_tx = 0' can't be moved in the entire handler due to a achievable race amongst the delay in switching to STATE_RX_AACK_ON and also a new interrupt, we introduce an intermediate 'was_tx' boolean only for this reason. There is absolutely no Fixes tag implementing here, lots of changes https://troyaglgk.mybuzzblog.com/8181389/the-2-minute-rule-for-wordpress-and-plugins