Yes: kefir prefers dairy milk if you use almond or oat or some non-dairy form then you are best off using either a mixture of non dairy and dairy, or switching off every few brews. The grains will become non-propagable (is that the word?)with continued use of non-dairy milks. I know this because I left my whole jar of prized grains in rice milk and they were not to be rescued. I recall hearing long ago that adding a bit of lemon juice to nondairy kefir will allow the grains to feed better and may help. Something to do with the acid that the microbes love.
You didnt explain: You did not ask for explanation LOL *Smile*
I hope that helps.