[Bug]: HOST_KEEPALIVE_FEATURE makes plugin not work

[classicrocker883]

Description of the bug

Taken from this issue here from @bdleung:
classicrocker883/MRiscoCProUI#168

Octoprint's Marlin EEPROM editor plugin does not connect to firmware

Plugin version

3.3.0

OctoPrint version

1.10.3

M503 Response

The M503 command in the Octoprint terminal did not seem to return any useful data

API Response

TBA

OctoPrint logs

TBA

[cp2004]

The plugin needs to get the M503 response from the firmware in order to read the settings. If you're getting nothing out of this, then the firmware needs fixing to provide this output. If host keepalive is preventing this from being sent, it needs to be fixed.

The host keepalive feature seems likely to be a red herring (or some special bug triggered with this) - since every test that you've performed since it was broken worked, you should do one more test enabling only this again to make sure it definitely breaks.