I discovered these bugs in SVN version r4471.

First bug involves emulated EGA card (as set in dosbox.conf). When running with an emulated EGA card, the Aspect option being set to true is ignored in text modes. That is to say, it doesn't force the text modes to have a 4:3 displayed aspect ratio.

Second bug involves emulated CGA card (as set in dosbox.conf). When running with an emulated CGA card, the Scaler option ignores being set to forced (such as "normal2x forced"). That is to say, it doesn't force the display to be double sized in text modes.

I don't know when the second bug came into existence, as I know "forced" in the Scaler option has been available for a long time, but I just hadn't used it until today. I do know that the first bug though came into existence within the latest SVN version(s), as the last normal release version of DosBox (0.74-2) never supported a forced 4:3 displayed aspect ratio in text modes (only in graphics modes did it work in the normal released versions). So I assume as the developers were adding this feature (using the Aspect option even in text modes) in the SVN version, they failed to test it in with the emulated graphics cards, and thus the bug hasn't been caught until my bug report here.

Note to devs: Whenever you add a graphics feature regarding options such as Scaler or Aspect, please test it with each emulated graphics card type, so as to make sure it's actually fully functional. Also I didn't do a comprehensive test myself to see which modes have the bugs I described. All I know is that bug 1 for sure occurs in EGA, not CGA, and not in SVGA_S3; and that bug 2 for sure occurs in CGA, not EGA, and not in SVGA_S3. I ask the developers here to test each of the bugs I described in all of the emulated graphics cards available in DosBox, to determine the source of the bugs so that they can be fixed.

UPDATE: regarding bug 1.
I discovered that it not only prevents forcing displayed aspect ratio to 4:3 in text mode, but also prevents the forcing of the 4:3 aspect ratio in graphics mode.
Also I discovered that this bug was also present in DosBox release version 0.74-2. Though it doesn't affect text mode in that version (as text mode in that version couldn't ever be forced to 4:3 aspect ratio), it certainly affects graphics mode.

UPDATE2: regarding bugs 1 and 2.
I did more testing here (in SVN version r4471), and found that bug 2 affects not only emulated CGA graphics card, but also the other two similar emulated graphics cards (Tandy and PCjr).
Also, I discovered that neither bug is present in the emulated Hercules graphics card, and also neither bug is present in any of the emulated VGA graphics cards (from VGAONLY on up through VESA_OLDVBE).