Inflight CDI Ignition Failure

[fodrv7]

My RV-7 has a Magneto on the left side and a Light Speed CDI system in place of the Right Magneto.
On reducing RPM after Take-off today, I found that there was no RPM Indication, which immediately led me to suspect that the LightSpeed CDI (from whence the Engine Monitor obtains RPM) had failed.

Selecting the Right Ignition confirmed the failure.

After landing it was found that the plug on the Hall Effect Module had come out.
This same failure occured to an RV-7 hangared next to mine.

I would be interested to know:
1/. If any other owners had experienced this problem, and;
2/. Has anyone developed a method to Lockwire the plug in place.
Pete.