Non-mech units loaded from cache sometimes save with mtf extension

[assaultdoor]

Using MML 0.47.4 on OS X with Java build 1.8.0_51-b16, when I load some non-mech units from the zip files that come with MML, they save with a file extension of mtf rather than blk. I also don't get the "Save As" window, which is usually what happens when I save a unit that I didn't just load directly from disk. Instead, MML automatically saves it to data/mechfiles/

This may actually be an older bug reported as closed here: https://sourceforge.net/p/megameklab/bugs/166/

I've been testing this, and it seems that the first time I load a particular unit type (combat vehicle, primitive combat vehicle, ASF, Warship, JumpShip, etc.) from the cache, the Save As menu works normally. Every unit of the same kind that I load after that, though, has trouble when I try to save it. If I switch to a different kind of unit, everything resets.

So, for example:

1. I load AC/2 Carrier (Standard) from the cache and try to save it. I get the "Save As" window. I cancel it.
2. I load AC/2 Carrier (Standard) from the cache again and try to save it. I get the bug.
3. I load Aegis Heavy Cruiser (2843) from the cache and try to save it. I get the "Save As" window.
4. I load AC/2 Carrier (Standard) from the cache. I get the "Save As" window.
5. I can repeat steps 3 and 4 without encountering the bug. But, if I load two WarShips or two combat vehicles in a row, I get the bug.

And apparently 'Mechs also do this, but at least they should have the mtf extension.

Also, while I was testing it on AC/2 carriers, I noticed that when the bug happens, MML tries to save the slash character in the name. I'm running OS X, and the slash is a directory separator, so it's trying to save the file "2 Carrier (Standard).mtf" into the directory data/mechfiles/AC/. It won't create the directory, but if I create an AC directory, it saves the file with the incorrect .mtf extension.

Correction: This same thing happens when I load a unit from the cache that is not in a zip file. The first time I try it, I get a Save As window. The second time, it automatically saves to the directory where the unit was already saved (so data/mechfiles/customs/ for me).