Loaders with lane filtering enabled are entities of type aai-lf-loader (which I guess are introduced by this mod), whereas AAI loaders are aai-loader. While AAI-loaders can be upgraded via upgrade planner, the aai-lf-loader entity does not seem to have an upgrade path (possibly due to it being a hidden type?).

How to reproduce:

• Have AAI Loaders and Loader Utilities enabled

• Place Loader (enable LF if default is off)

• Try to upgrade via upgrade planner -> doesn't work

• Disable LF

• Try to upgrade -> works

You need to have the mod setting on to show all loader entities. I'm leaning towards changing that because I keep seeing people report it as a bug.