It's not a easter egg or a mod. That collision simply has a wrong material ("FREASH_MEAT" instead of "GLASS_BULLETPROOF") assigned to it.
As for it not working for you, it's because you either have the MP map enabled (R* fixed this for the "mpapartment" dlc collision) or have Map Fixes installed.
You can get rid of it by editing "vfxfogvolumeinfo.ymt" with CodeWalker.
If you don't know how to do it, you can get an already modified version that i included in this mod.
Graham's Number:
It's VERY large. If you took all of the known matter in the known Universe & converted it into ink there wouldn't be enough to finish writing the number down it's that big.
You learn something new every day (no, i'm not joking).
For simplicity's sake. We'll call it zero chance.
Great 
(now i'm joking lol).
Hope you get it sorted out, the whole wheelie thing is a total
idea (even for Rockstar). I laughed when I saw it. Thank f**k we're able to remove it relatively easily
Nice to see that i'm not the only one that dislikes it
Well, i guess i'll go and edit those files then, thanks.
With the Arena War update, R* added a wheelie mechanic to all the muscle cars in the game.
I would really appreciate if someone could make a script to disable this feature (since doing it from the handling.meta/vehicles.meta/or whatever other file would be a pain ).
0.050 0.000 (old gen) instead of 0.000 0.000 (PC).
Open timecycle_mods_4.xml (update/update.rpf/common/data/timecycle) and search for phone_cam1. Remove all the values and then paste these ones:
<postfx_desaturation>0.750 0.000</postfx_desaturation>
<postfx_noise>0.000 0.000</postfx_noise>
<postfx_vignetting_intensity>0.975 0.000</postfx_vignetting_intensity>
<postfx_vignetting_radius>10.000 0.000</postfx_vignetting_radius>
<postfx_vignetting_contrast>0.250 0.000</postfx_vignetting_contrast>
<postfx_vignetting_col_r>0.024 0.000</postfx_vignetting_col_r>
<postfx_vignetting_col_g>0.035 0.000</postfx_vignetting_col_g>
<postfx_vignetting_col_b>0.047 0.000</postfx_vignetting_col_b>
<postfx_scanlineintensity>0.100 0.000</postfx_scanlineintensity>
Also change numMods from 39 to 9.
Note: you still need to toggle the filter (the first one).
The reason i updated the game to After Hours. Keep it up!
@Reacon I think it's defined in the vehicles.meta but at the same time it's also connected to the game .exe (and if something related to that "function" is missing, like when playing on an old/previous game version, then it crashes)
Note: i barely know anything when it comes to vehicle modding so take my words with a grain of salt
@Reacon I don't know as i never tried to do that