As mentioned above, this is most likely network related. We see this issue most with players that have an upload speed of less than 1Mbps, but historically the “Player List Plus” mod has been known to result in similar issues.
Other than exploring what could be causing this recent instability in your connection, you may benefit from enabling the ‘Small Network Packets’ option within the ‘Network’ panel. Although, please keep in mind that this option cannot be used in combination with the ‘Player List Plus’ mod.