Error competitive rating

Hi, I think my competition game rating has some issue. It suppose to be one rank up after every 5 wins right? but I have to win 10 time to rank up from diamond 4 to 3, this also happened when I ranked up from diamond 5 to 4. And after my recent 5 wins, I acuatlly ranked down to 4 again. Anyone has the same bug as mine?

Rank placement and rank adjustments take into account more than just wins and losses, they are also affected by how far apart the ranks are between you and your opponent, how new your account is, and how long ago you last played. Newer players have much more drastic rank adjustments due to the lack of performance history to base initial skill and inactive players similarly have more drastic rank adjustments due to the lack of recent performance history. Both of these are potential explanations as to how players that are grouped and play the same matches can end up with different ranks. Feel free to read the updated Developer Blog explaining rank adjustments here: Competitive Play Update – Teaming up for better matches - News - Overwatch. However, if you believe this truly is a bug, then please do check out the competitive bugs megathread linked at the bottom of this post, which archives and documents almost every competitive bug. I’ve compiled a list of similar posts regarding similar bugs under: Incorrect Rank Adjustment. Please help in spreading the word about this megathread and other related threads regarding these issues.