Aside the above, i also have never left a position open for more than two hours, infact I rarely leave a position open for more than one hour,
Which is why you didn't notice the effects of funding rates yet. Most exchanges have a new funding rate round every 8hrs.
@OP, as @adaseb said, funding rates can shift brutally on low-cap altcoins. So, if it does affect your trading style/strategy, just stay with btc and eth. Or just spot trade on alts, or just close your position a few minutes before the funding count comes in and re-open it afterwards again. But you may miss some price action since the rates are triggered at the same time the hourly and 4 hourly candles closes in. This is how it is and we gotta get used to it.