Ranked placement not working or consistent

I finished season 8 at plat 4 and have been playing ranked games as off roles to try to learn new stuff. I have lost a few but I have not dropped out of plat. However as of last patch the border around my profile during the loading screen has changed from plat to silver. Anyone know what might be causing this? Also I wouldn't mind being silver to play with my friends but I am not able to match ranked games with them.