Conditions with blocks return differently when the looped stuff isn't a variable

[TPGamesNL]

Description

The solid condition doesn't work in loops when the given values to loop aren't variables (this is a terrible description but you should look at Steps to Reproduce, it's more understandable).
Same for: is transparent, is flammable

Steps to Reproduce

on rightclick on sand with diamond hoe:
	loop block above and block below:
		message "&21 &r%loop-value% (%""&atrue"" if loop-value is solid, else (""&cfalse"")%&r)"
	set {_b::*} to block above and block below
	loop {_b::*}:
		message "&32 &r%loop-value% (%""&atrue"" if loop-value is solid, else (""&cfalse"")%&r)"

Expected Behavior

The condition should return true or false consistently in both loops.

Server Information

• Server version/platform: Paper-94 (1.14.2)
• Skript version: 2.4-alpha3

[TheBentoBox]

Well that's weird.

[Whimsyturtle]

Will try and investigate this later

[Whimsyturtle]

Oddly enough, I found that this was caused due to the internal use of ItemStack, hence this issue is fixed by #2510