When the mod is installed, the Laser technology which is a prerequisite for Laser Turrets is not visible so you can't research it or techs that require it, like Laser Turrets. The same goes for flammables, you can't see it in the tech tree

I suspect it's because of "hide_empty_techs.lua" since both of these are techs which don't unlock anything on their own, but are primarily techs that are prerequisites for other techs. There may be other issues from this as well, but these are 2 i've found.

This is with factorio v2.0.66, mod version .87 and not using Space Age. The issue occurs even with no other mods enabled

Edit: Confirmed that with the line to hide the techs commented out, it's fixed and both those techs are visible again.

Sorry about that, that was meant to clean up some old placeholder techs that I had, Its been patched now

Thanks for the quick fix!