I just had my MCU replaced and had the same problem with my homelink. (2013 P85) When I was at home the link would turn green but did nothing when I pressed it. It didn’t show the little transmit icon when I pressed it anymore. After many failed attempts at relearning it and several reboots - I was able to fix this problem by deleting all of the driver profiles and performing a factory reset on the MCU and starting over. After I reset it and created new homelinks, everything was back to normal. Give it a shot, I didn’t want to factory reset it but that ultimately fixed it.
I recently had the MCU1 in my 2013 replaced as it was getting flakey. When I got home, my Homelink integration no longer worked. The items were there in the list, but they no longer worked so I reprogrammed them.
After reprogramming, Homelink only sort of works. It works in the garage, and it works when the car is facing the garage, but if the car is facing the street it won't work. Even if the trunk is as close as possible to the garage.
I relearned the remote a bunch of time, trying different locations near the bumper to hold the opener. I replaced the batteries in the opener. I fiddled with the garage door opener antenna. Nothing worked. I spent 3 hours trying every permutation of sensor, location, etc.
Mobile service was out and did a hard 12V reset on the vehicle. We also removed the front license plate. No luck. They were similarly stumped. They're going to investigate logs, but didn't sound hopeful there would be a solution.
Any idea what could be going on here? Literally the only change was the MCU1 swap, but Homelink is a little module in the frunk. They shouldn't be related. I don't even know what more to try.