Steps to reproduce

1. $ vim --clean testfile
2. set autocomplete
3. populate registers with yy, "ayy, etc.
4. enter insert mode
5. <C-X><C-R><C-X><C-R>
6. observe single word register completion

Whole line ins-completion also has the same issue, follow-up invocations of <C-X><C-L> don't insert lines as expected.

Expected behaviour

Pressing <C-X><C-R> twice should give full register completion.

Pressing <C-X><C-L> repeatedly should insert follow up lines.

Version of Vim

9.1.1646

Environment

Operating system: nixos unstable
Terminal: tmux 3.5a
TERM: tmux-256color
Shell: fish 4.0.2

Logs and stack traces