Can't get read-only values of Items

[motrar]

Describe the bug
Some item's values ("amount" and "dmamount" for example) can't be read using script, always leaving NIL value.
I assume it's any value which is read-only.

To Reproduce

1. Have a friendly with HP lower than their max HP.
2. Have, or spawn a health pickup on the ground.
3. Let the friendly pick it up.
4. Friendly doesn't get healed because of invalid value.

Tested on map t1l3 in Spearhead.

Expected behavior
In Vanilla, values are read properly and no errors occur.

Version information (please complete the following information):

• OS: Windows 10
• OpenMoHAA Version: 0.83.0-dev+1159.a2f3401 win_msvc64-x86_64