Nope. It's some kind of macOS bug. I ended up fixing it by adjusting the underlying Apple Script to this:
on alfred_script(q)
set chars to count (get the clipboard)
if chars > 500 then
do shell script "afplay /System/Library/Sounds/Funk.aiff"
else
tell application "System Events"
set _index to 1
repeat with letter in (get the clipboard)
keystroke letter
delay 5.0E-4
end repeat
end tell
end if
end alfred_script
I've been using it just fine since.