Usually if it looks like powders are passing thru my filter its just fats and lipids. In my experience a cold extraction isn’t sufficient to stop waxes from being extracted, at least not with an alkane. But I also don’t extract at -80, if I did my seals would probably crack because I don’t use ptfe gaskets.
Filter papers are not as effective as something like @Curious_Roberto suggested. Depth filtration is especially suited to filtration of very small particles from solution and the cost of the filter media is comparable to filter papers. You can make a small depth filtration cartridge with a filter plate and some rolled up filter cloth sheets. You can send solvent thru them to clean them for reuse, which you can’t do with filter papers.
Sounds like waxes that were extracted and then precipitated on the cold steel surface of the material column.