Client slowdown after several games (friend having same issue on different hardware.)

The problem started a few days ago. Personally I haven't had (much of) an issue with the new client up until now. However after playing between 3 and 5 games there is a noticeable slowdown in navigating the client. Be it selecting champion, changing runes, accepting queue pop, choosing queue types, ect. The issue continues to get worse until I fully exist out of the client and relaunch it. A friend I typically duo with is having the same exact issue as well. It feels like a typical memory leak issue. It gets to the point where it can take 3-5 seconds to swap out even a single rune, and scrolling through the champ list can take as long as 20 seconds.

Not sure of bud's exact hardware specs, but running on a mid range gaming box here.

Win10 Home 240gig SSD Boot Drive (League is installed on the SSD, 90GB free space) 2TB Storage Drive i7 8700k GTX 1070 16GB DDR4.

No issues in game, just the client. Typically see 130-170fps and 29-33ms ping times.

Thoughts? Had a couple games in the past few days where I didn't restart after 5 games or so and was unable to completely swap runes, or unable to save rune changes in time due to this issue.