As a follow-up to my previous comment (in case anybody is listening), I found out that I could also work around the issue by printing anything on the console, before switching to gfxterm (so, without any delay). E.g. with the following:

echo "Loading bootloader..."
terminal_output gfxterm

No video output on some systems

Description

GRUB is functional but does not output video. It can be navigated blindly and does boot Linux/Windows.
The issue seems to be that gfxterm crashes if load_video hasn't had enough time to set up the video mode.

Systems

Affected

• Thinkpad X1 Carbon Gen 3 (Intel i5-5300U, Intel HD Graphics 5500) running Arch Linux
• VMware Fusion virtual machine running on an old Mac Pro with Arch Linux
• Other users running Ubuntu have also reported this issue; see the source for the workaround below

Unaffected

• My desktop PC (Intel i7-7700K, Nvidia GTX 1080) running Arch Linux
• A VMware Workstation VM (hosted on Windows on my desktop PC) running Arch Linux

Workaround

Editing 00_header to include sleep .1 or sleep .5 between the lines load_video and insmod gfxterm. This works on both of my affected machines. However, the workaround has to be manually reapplied after each update, which are relatively frequent on Arch.
Here an excerpt (with line numbers for easy reference) of 00_header with the workaround in place:

196   set gfxmode=${GRUB_GFXMODE}
197   load_video
198   sleep .1
199   insmod gfxterm
200 EOF

The source for the workaround is this discussion on Ask Ubuntu: Grub menu working but hidden, can't make it visible.

Additional Information

• Disabling gfxterm and using the text console instead also works, but is less visually appealing.
• Trying to use other, different video resolutions does not work.
• The last GRUB package on Arch that worked for me without the workaround was version 2.06-5.
• The last unaffected version on Ubuntu is unknown to me.

Here is the /etc/defaults/grub from my Thinkpad (out-commented and empty lines removed):

GRUB_DEFAULT="saved"
GRUB_TIMEOUT="5"
GRUB_DISTRIBUTOR="Arch"
GRUB_CMDLINE_LINUX_DEFAULT="usbcore.autosuspend=5 retbleed=stuff"
GRUB_CMDLINE_LINUX=""
GRUB_DISABLE_SUBMENU="false"
GRUB_PRELOAD_MODULES="part_gpt part_msdos"
GRUB_DISABLE_OS_PROBER="false"
GRUB_TIMEOUT_STYLE="menu"
GRUB_TERMINAL_INPUT="console"
GRUB_TERMINAL_OUTPUT="gfxterm"
GRUB_GFXMODE="2560x1440x32"
GRUB_GFXPAYLOAD_LINUX="keep"
GRUB_DISABLE_RECOVERY="true"
export GRUB_COLOR_NORMAL="light-red/black"
export GRUB_COLOR_HIGHLIGHT="light-magenta/light-blue"
GRUB_BACKGROUND="/boot/grub/hackers.png"
GRUB_SAVEDEFAULT="true"
GRUB_FONT="/boot/grub/unicode.pf2"

I created this bug report here instead of the Arch Bugtracker because it seems to be not necessarily specific to Arch. If that is not the case, or if there is anything else I can do, please let me know.