lavaalpha issues in ne_ruins (invisible lava)

[Placo]

In the "Altar of Storms" mod:
https://www.quaddicted.com/reviews/ne_ruins.html

At some point during the second map the lava rises and floods the lower part of the level. It is invisible in vkQuake.

I noticed this bug just as vkQuake was archived nearly two years ago so I couldn't create an issue here but then I was reminded of this bug today.
The problem appeared around the time Temx reworked the engines' alphasorting, the mod was working fine in vkQuake in older versions.

I have tried disabling r_alphasort but it doesn't change the problem.
I noticed that r_wateralpha is at 0.7 and r_lavaalpha is at 0.
Changing either r_wateralpha or r_lavaalpha to 1 makes the lava appear, but any other value (between ==0 and <1) the lava is invisible.
I don't know if the issue is caused because the lava is invisible at the start of the map or what (as it rises during the level).

I use vkQuake in Win10 with a geforce980

In vkQuake:

In Ironwail for comparison:

A save to the spot with the problem:
save.zip

[j4reporting]

It seems that the "lava" in this map is a bit different from the usual lava (e.g.. id1/end ), as it is always rendered with r_lavaalpha 1 in ironwail and quakespasm. The value for r_wateralpha of 0.6 is not applied here ( r_lavaalpha "0" ).

[j4reporting]

first bad commit is 810725b
"Separate worldmodel water by transparency status"

It looks like only lava parallel to the floor is rendered incorrectly.
I think this map is using entities for lava with alpha 1.0 ( r_drawentities 0 ) will remove all lava

r_lavaalpha 1:

r_lavaalpha <1:

r_lavaalpha 1:

r_lavaalpha <0: