they do rise though? Is this plant canopy closer to light? it'll cower more often as it gets too much light -- up and down still, but more often down than normal.
if you have fed well lately, ease off for 1 or 2 irrigations with no fertilizer. See what happens when you reset the substrate a bit.
other things... plants look pretty droppy if the pot size isn't big enough. a rootbound plant droops a lot.
if you have a regular system and schedule.. which it seems you are fairly organized.. even if not rigid, it's safer to assume it's somethign that's been added than something missing. and, much easier to adjust course the other way if that proves to be false with a short amount of time... not true of going the opposite directions first.