Login / initial OpenRC output broken after Plymouth install

[finnvanhee]

On my relatively new Gentoo installation on a Dell Latitude E7250, I have recently been experiencing strange behavior of the virtual terminal. This started after a session in which I did a variety of things, but the main action I took was installing the Plymouth splash screen program. The first time I booted to test this, the splash screen only loaded a few seconds after the boot process was complete, preventing me from logging in as there was no way to remove it. I prevented this by booting into recovery mode, which stopped Plymouth from starting. I then removed Plymouth, but a problem persisted; the initial OpenRC output screen would appear at the same time as the splash screen used to. I could still switch to another TTY to use the computer. A few boots later, the problem changed. OpenRC started refusing to start any services until I pressed a key such as the arrow key; this occurs for each service, but if I hold down an arrow key, it starts services at the normal speed (with some visual artifacts). Once it is done, when I try to log in on TTY1, the tmux session that I configured to start automatically prior to the start of the problem quits with the message