Light period cause for concern?

I don’t remember my periods before birth control because I was on it for five years (been off for 3) but now my periods are like 1.5 days. Whenever I did fertility blood work, nobody was concerned because I get positive OPKs and my period comes regularly 28 days. But—isn’t a light one some kind of sign that something is wrong?

Don’t tell me to get checked again. Saving money to try and adopt because TTC still isn’t working. Just curious to see if anyone who has had testing has dealt with light periods and been told something.