The message "Losing UDP, switching to TCP" has to do with packet loss on the Internet connection. However, it is possible for this to be exacerbated by a computer which is running out of resources, or by a router which is having problems.
Or if you are running two computers, on the same network, and running Aces Hioh behind a router which does not support UDP over NAT, it can cause it as well.
Or you are running over a wireless connection which will almost always have some bit errors in the data stream which will for the switch as UDP cannot be retried.
If it is the Internet, using Ping Plotter should show where the packet loss is occurring.