Hi! I have to dispute your claim; my tests show everything is working perfectly. Debug mode confirms this as well.
Let's look at the numbers: the damage bonus against enemies drops by 3% with each warp between planets, while mining a single Exocine crystal boosts damage by 15% - meaning that after five warps, you will have completely negated the effect of one Exocin crystal.
If you want to check this yourself, the easiest way is to enable debug mode in my mod's settings; you will then see additional information when warping. Enjoy the game :)