Hopefully to help others.
We had an EI CGR-30P installed last year. Since then we have had numerous sensor issues; EGT #1 and #3 along with oil pressure have been repeats. Several of the local mechanics hate the OLC-2 connectors saying they are very prone to poor connections. EI claims they are the best they have found.
After the CIES senders were installed, I found the wires pulled out again and re-connected them.
Then I got to looking. Seems the failures are all on the same side, in the same place. And the same place is
exactly where a person would lay their forearm on the engine mount to change the oil filter.
Ergo, the problem isn’t the connectors, it is their installation along the top of the engine mount tube. Next oil change they will be moved so the tube protects them.

The wire EI uses is a very fine solid wire. It's easy to break the wire if the allen screw in those connectors is over torqued/

I just installed an EI MVP50 system, and the connectors cam with a larger crimp on ferrules for there small wires. They must have had issues and came up with these to help with over torqueing the set screws on the OLC-2 connectors. I have 0 flight time on this system yet. hopefully soon though!

I have had an EI EGR-30P installed in my C180B for several years without connector incident. Presumably they use the same coupling connector. I support the connector and adjacent wire with either clear nylon tubing or silicon tape covered with nylon spiral wrap, along with a few tie wraps for security. Both are illustrated below:

EI overlap connectors were originally just one set screw. Then they lengthened them and added a second set screw. Now they have a crimp-on part for each wire end before they get inserted into the OLC-2 with 2 set screws.

It's pretty common to find erroneous readings on new installations in the first 100 hours (or more) with the OLC-2 connectors. But you see some failure rate with the other types of connectors too if great care and attention to detail isn't applied during the stripping/crimping process.