loading themes superficially reverts doom-big-font-mode

### What did you expect to happen?

Upon loading a new theme (SPC h t), I expected the already-engaged big font mode (SPC t b) to remain in effect.

### What actually happened?

As soon I select a theme from presented menu (upon doing SPC h t), the new theme is turned on, but also the font collapses to regular size. I would expect that the big font would remain in effect, despite any theme or other cosmetic changes.

### Describe your attempts to resolve the issue

Interestingly, if I follow this up with another toggling of big-font mode (SPC t b), nothing changes, font still stays small. Only on the second attempt to toggle big font does it kick back in. This is my current workaround. To me this suggests that there is discrepancy in Emacs state (it thinks big font IS engaged) and rendering (renders small font instead).

### Steps to reproduce

1. open emacs
2. SPC t b -> note big font
3. SPC h t and select any other theme -> note the font switches to small/regular, w/o being asked for

### System Information

https://pastebin.com/6P1Y1F5F