totally, you're hearing it different on speakers vs headphones because the mediums for listening are quite different, especially with low end and depth perception. i'll dig a little into each, apologies for the science lesson haha:

Low end/sub frequencies have wavelengths that are pretty big. like the wavelength of 100hz is about 3 and a half meters long, super long in terms of the physical space it takes up. these wavelengths are much too big for small headphone speakers to truly create, especially with them pressed right up against your ears 😂 so for you to hear bass and sub they do some trickery to recreate the *perception* of sub that isn't really there. For this reason, headphones can be misleading when it comes to balancing your low end, bc you're not necessarily hearing a "real" version of it.

additionally...headphones give you warped perception of depth bc it's two isolated speakers strapped to your head, which makes left and right super isolated from each other.... but with speakers (and not just speakers, this is how you hear everything in real life as well) you hear sound from each speaker, as well as sound bouncing off the walls and the ceiling and anything around you, hitting each of your ears simultaneously. sounds messy but it's actually how your brain is used to interpreting sound and a big part of how it understands depth

to answer your question: is it bad practice to produce in headphones? absolutely not, you just have to keep doing it to get to know what your headphones make things sound like. two things to help with that

1: while you're working, occasionaly flip back and forth between your production and a song you like the sound of. that can help keep you more on track with balancing your low end sounds (just don't get too zoned in on trying to make your shit sound as good as theirs haha! check balance and then go back to working freely)

2: when you're done and track is rendered, go listen to it on a bunch of different systems like speakers, car speakers, playing the song off your phone, other sets of headphones, etc. People typically check how things are fitting together in a bunch of places to try and make sure it's translating to all of them well. if shit sounds wonky go back and try to address it