m0useanswered grow question 3 years ago I have noticed this as well. I will set it to Metric vs Imperial and it does not save it and defaults to one way or the other.
Sometimes I hit metric then edit and it switches back. Even if I hit metric again it saves it as imperial.
I find this can sometimes help. Sign out and clear caches and cookies then restart comp/phone.
If it still locks it to the metric or imperial input the equivalent value. 5gal=18.93L and it should save that and when the sites done bugging out it will be saved as the correct input.
Good Luck!