Eidelan

I'm a new player and am hosting a 1.21 server on an Ubuntu Server VM. So far everything has worked well, except my friends playing remotely are only able to type one character into their Survival Handbooks when trying to search for things. If they type a second character, it will overwrite the first character they typed, and the search results change to entries starting with the second character they typed. I'm playing on the same LAN as my server and haven't had this issue. We are all playing using the latest available Windows client with no mods enabled. I haven't been able to find anything about this online yet. Has anyone else come across this/have any troubleshooting tips? Any help/guidance would really be appreciated.