I have had the same problem using a X8R receiver in a CDI 40 cc powered tug plane. Crashed on maiden. Rebuilt and flown, but fortunately it failed again on the ground while tied down doing engine telemetry tests.
I have now got rid of all my "X" series receivers after reading many reports of similar lockouts. See this thread and others:
Alert Frsky Taranis Rx lock out Radios
www.rcgroups.com
I now have a good stock of the older "D" series receivers as I swapped my fabled "X" series receivers for some to add to my stock.
I figure what "D" series I have now will serve me for the remainder of my active modelling career.
I will be very happy to leave behind me all the notices about "emergency upgrade required" and the like.
FrSky is sadly going the way of other former very good companies; Toyota, Volkswagen, Boeing et. al.