If you have the same water I have then lowering TA would be a good thing. I doubt that it will be much of an issue in that way.
Much more important I think is that the pine needles in the skimmer can cause the system to suck air, drawing air into the pump basket and the pump and the filter. The pump does not do well with air in the system. If bits of pine needles get past the skimmer they can mess with the pump impeller also.
I suggest that you may want to use skimmer socks to do an even better job of catching leaves of all sorts. And then you will have to remember to check them often, maybe every day in the fall, maybe twice a day if it is stormy. They are great in the spring pollen season. Not great if you pour bleach into the skimmers as that will destroy the sock pretty quickly.
I'll throw my 2 cents in here since I have MASSIVE issues with pine needles due to 100 ft. white pines all along my property line which is adjacent to the pool. Let me point out that they are not mine or they would have been gone a long time ago! I keep skimmer socks in both skimmers but STILL have to clean the impeller every other weekend. Those needles will get into that impeller even with the socks, but it is critical that you have these. But, to your question of pH, I don't really notice much change in my pH. I have a SWG which is supposed to increase pH somewhat but mine doesn't seem to. Maybe this is where the pine needles come into play.
I would strongly suggest you check your impeller for needles. Mine will wrap around it like strings in a vacuum! This may be keeping your pump from running properly which might really be the issue with your pH. Just my so humble opinon! Good luck!