@RiotRepertoir - A question regarding "demotion protection"

How does it work and what triggers it or does it have a "cooldown"?

In the last few days, each time I promotes, the 1st loss after I got to 0 LP would demote me, no matter if I slowly dropped from 50 LP or it was straight the first loss after I promoted, but according to the "Ask Riot" thread on matchmaking, that shouldn't happen at all due to the demotion protection acting like a safeguard for 2-3 games or so, and only after losing a few games in a row at 0 LP, the demotion happens, but for the 3rd time now, first loss at 0 LP demoted me.

Before someone runs in and tells me "git gud" or something like that, on how I don't deserve the promotion, I haven't lost more than 18 LP nor have I gained less than 23 LP per match ever since I calibrated this season, and we were told that LP gain/loss is based on both avg MMR of the match and your MMR compared to the rest, so this gain/loss ration would imply that I am slightly better than my silver piers.

We all have bad matches, bad streaks, etc, we also have our own games where we play bad, but apparently, the protection set against those small drawbacks didn't work, or we weren't told exactly how it should work.

Thanks in advance