The derank from gold 3 to gold 4 is likely from the end of season adjustment, which takes into account any games that you played after your last rerank. The derank from gold 4 to silver 2 is from seasonal decay, which the Devs will be removing in Season 4. If you think these are bugs however, here’s a link to my post in case you’d like to read more: Comprehensive Thread Of All Top 500/Competitive Bugs.