Glad those changes seemed like they were helpful and that Plan Builder is laying out a plan you’re finding more appropriate!
AI FTP Detection does take into account your HR, but it weighs power much more heavily. Pressing lap buttons incorrectly on accident shouldn’t throw things off (especially if you’re still completing the workouts on the whole).
I do see that your Progression Levels are continuing to bump up as you continue training, which is good reassurance that you’re getting faster! If you keep on completing Productive workouts, I think you’ll start to see your FTP increase alongside your PLs – especially now that you’ve been back on a plan for a bit. Remember that consistency plus time is the key!
Regarding the 2-watt decrease, I’d recommend not worrying too much about AI FTP Detection right now – by which I mean to say, don’t read into it too much! You can correct me if I’m wrong, but it seems to me like you’re interpreting your recent AI FTP Detection as TR/AT telling you that you’re getting slower (which I don’t think is the case!).
As other athletes have also pointed out, it takes time to increase your FTP, and in the grand scheme of cycling training, one month isn’t a tremendous amount of time. Consider also your overall fitness – if you’re feeling stronger and your PLs have gone up, then that seems like a good sign to me (and is often a precursor to a future increase in FTP 
).
While I read above that you said your FTP could feel 20 watts higher or lower depending on the day, how does it generally seem to feel as you’re doing your workouts? With your previous training history, I bet you have a pretty good idea of how each zone is supposed to feel as you’re doing your workouts. Are your Sweet Spot and Threshold sessions, for example, feeling appropriately challenging? If so, that could be a sign that your FTP is set at an accurate value for you at the moment. I know we can get very focused on seeing our FTP number increase, but it’s also important to consider if it feels correct for where we are right now.
Overall, though, I want to reassure you that it looks like your training is on track from what I can tell. I can totally understand some frustration/confusion when your FTP doesn’t go up (I’ve been there many times myself!), but I think you’re heading in the right direction. If you stick with the plan, I think your fitness will keep trending to where you want it to be. 