immediately after watering, this isn't a bad thing, but a little more perlite or similar added to your substrate will fix that... if it persists for a long time after watering.. definitely add more perlite or similar... you want 50/50 mix with soil/peat. can get away with a little less with coco because it retains 2/3rds the water of a sphagnum peat-based soil or soilless substrate.
Too much light? are they fine in the morning / midday then drop last few hours of day? could be a bit too much light per 24hours. don't have to dim.. could reduce hours of light too. in fact if running 20-24hours, that elevates the likely chance this is what is happening.
After looking at diary, i'd wager it;s mostly how the substrate is made.. when wet it is suffocating the roots. This isn't "overwatering" this is a substrate composition issue.
Overwatering is dumping more than necessary on the plant at one time... as long as some minimal dryback/drinking occurs, this won't happen with 'too frequent' irrigations and a good substrate. people employ 2-3 irrigations per day and don't have droop like this -- pest and microbial prevention becomes a serious concern with a constantly moist substrate though.
You still want to irrigate entirety of pot with a little runof to be sure yo don't leave dry pockets in the soil. you'll jsut have to live with a little droop. Go to 50/50 soil/perlite mix (relative to existing perlite that may be in the soil, so you may need to do a little math) and it'll rarely happen. 55/45? 60/40? prolly be fine too.. this isn't like a chemistry lab experiment, but 50/50 has been shown to be an optimal mix by research. check out dr. bruce bugbee on youtube to verify that tidbit. not just some groupthink bullshit people repeat ad nauseum... there is actual evidence to back it up.