Here's why I suggested that you did not read my post in its entirety:
The first three suggestions in the link refer to getting Universal Control set up and working the first time.
Since my post clearly states that I have used it successfully, these suggestions are an invalid/irrelevant to my scenario. The fourth suggestion, regarding keeping devices within 3 feet of each other... My post clearly states that the devices are only 1 foot apart.. Again, this suggestion is obviously invalid/irrelevant to my scenario. The fifth suggestion, of putting the devices to sleep and waking them back up... My post clearly states that this is specifically how I get Universal Control to work again... So again, a completely invalid/irrelevant suggestion. The very last suggestion (to turn off Universal Control, reboot both devices, then turn it back on) could technically be a valid suggestion - But when you read that I can easily get it to work again after locking the iPad, then this suggestion also becomes invalid/irrelevant. The link you included is simply the generic instructions from Apple of how to use Universal Control.
Being an I.T. Support person myself (for 31 years), I appreciate forums like this where people can help each other. However, anyone can do a quick Google search and find results that do not apply to the scenario at hand. That is exactly what this appears to be (and I did a pretty extensive search before I decided to post this here for help). Having read my entire post, you'd know that none of the suggested solutions actually apply to this situation.
