Are there repercussions if you do not submit a promotion packet for PSB and submit one during the deployment?

"I was told"... by whom?
If you are on a joint manning document that is graduated by MOS and skill level - as it should be - then you are going unless something happens that makes you non-deployable. The only meaningful impact from making Captain is the change to your PME completion vs your rank. This is one of many things your commander needs to talk through during validation, but a minor one.
I'd suggest you ask more pointed questions about how this conceivably negatively affects you or your unit's readiness to execute the mission.
SPOILER ALERT: It doesn't.

Well I cant speak on officer promotion too much. But my old Lt who is now a major didn't put his packet in for Cpt during deployment back in 2011 he is now a major. So I don't think it would hurt you. I have recently declined SFC promotion because of what I want to do with my career. Just remember it is your career Sir first and foremost if the deployment is what you want right now I would hold off on the packet.

I would not take the promotion. I would be thinking that O-3 will come soon enough. You can be more effective as an LT and gain so much experience and have more troop time. After command what is really left to do? If you like the troop time please take it and make a difference. Some will see what you are doing and know that your heart is with your men and this demonstration will be more rewarding for the Army, your unit and yourself. That is what I would do. I had a difficult time adjusting to the reserves as the standards were just too high for me after leaving active duty. What I know now, I would have been more useful to the reserve components as I would be thinking more about the long term. Sometimes there may not be a slot for an O-3 and you may have to seek another unit. Anyway, you will have to decide for yourself....I have seen some very mature LT(s) that put some CPT(s) to shame.