Via the Rocket League blog:

CHANGES AND UPDATES

Arenas

• Brightness on DFH Stadium (Day) and Champions Field (Day) has been reduced
• Fixed an issue with the grass in Celebration Stadium (Day) on low detail
• The broken texture on Starbase Arc has been fixed
• Mac/Linux: Farmstead map visuals have been updated
• Lighting on Farmstead has been adjusted
• Urban Central boost locations are now consistent with other Standard Arenas

BUG FIXES

General

• Boost audio will no longer cut out when rapidly tapping the Boost button
• Season Reward Level progress should now display correctly at the end of Competitive matches
• Added additional checks to prevent undesired demolish scenarios reported since the Autumn Update
• Fixed several issues with in-game grass
• The appearance of grass on lower detail modes on PC has been updated as part of ongoing optimizations
• Fixed the item thumbnail for Halo toppers with a Black ‘Painted’ attribute
• Fixed a game crash issue related to the Season 4 Reward Trails
• The ‘Labyrinth’ Decal for Takumi has been fixed
• Second player in splitscreen mode is not retaining color choices made in the garage
• Joining Free Play during join countdown blocks player from joining match

KNOWN ISSUES

• Some players on Xbox One may still experience performance issues
• Restarting Rocket League can help solve this issue temporarily while we continue to investigate