Bad understand line?

For some reason this understand line doesn’t seem to work (including Metric Units):

Typing “cool me by 5C” results in “I couldn’t understand that sentence”.

Can’t reproduce it in a minimal 6L02 project:

[code]
Include Metric Units by Graham Nelson.

Cooling it by is an action applying to one thing and one temperature.
Understand “cool [something] by [temperature]” as cooling it by.

Lab is a room.

Report cooling: say “You cool [the noun] by [the temperature understood].”[/code]

Edit: Ah wait, “cool me by 5C” isn’t understood, so it’s case-sensitive. Bizarre.

Edit-Update 2: Same thing with powers:

[code]Include Metric Units by Graham Nelson.

Cooling it by is an action applying to one thing and one temperature.
Understand “cool [something] by [temperature]” as cooling it by.

Charging it by is an action applying to one thing and one power.
Understand “charge [something] by [power]” as charging it by.

Lab is a room.

Report cooling: say “You cool [the noun] by [the temperature understood].”

Report charging: say “You charge [the noun] by [the power understood].”[/code]

This doesn’t happen when there’s a space between the number and the letter, though – if you use electric charge, “5 c” and “5 C” are both understood.

Looks reportable!

Reported. The issue doesn’t arise with test scripts, so I suspect that something is going wonky with the built-in interpreter.

It’s a parsing bug, not an interpreter bug. This is a case where Glulx is not exactly the same as Z-code (it leaves capital letters in the input buffer). The generated unit-parsing code does not cope with this correctly.