Weird LP gains after reaching D4

This question is for Riot Support and for anyone who knows what Is going on. I have been climbing pretty consistently up the tank ladder this season but something odd has happened after reaching D4 rank. I was getting 22 LP a win while I was in Plat 1 but as soon as I hit D4 elo I am dropping down to only getting 15 or so LP a win. I am not sure why this happened but it seems extremely odd. If anyone could give me a clarification, that would be great. Here is my OP.GG
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