Why would GPG Pinentry be slow when opening in GUI but instantaneous when opening in CLI?

Having a hard time figuring out the debugging steps for this behavior. I'll run some gpg command and, typically, about 20 seconds later a GUI Pinentry window will pop up where I type in my password and the command proceeds. Occasionally though, the prompt instantaneously appears in my terminal (without me changing any config). On other rare occasions, the GUI Pinentry will be instant. One time I noticed the GUI Pinentry was instant was when I was running on a single monitor. I typically have an external monitor connected to my laptop over HDMI. Another time I noticed I was getting prompted in my terminal was when my window manager had crashed, I killed the Xorg server process from a seperate TTY, then re-started my window manager. I'm running Manjaro Linux with StumpWM as the window manager. I'm not sure what other pieces of software or config are relevant to this.