Bangle.js program being read partially and giving errors

I have been working on a Bangle.js app for work. After leaving the code to run for a while, the app starts throwing errors continually (probably once every time some event is fired). The errors thrown were very peculiar to me. For example in latest build:

Uncaught ReferenceError: "ointStep" is not defined
 at line 1 col 1
ointStep(){var
^
in function called from system

(where the function in question is supposed to be notifyCheckpointStep(), is not even a function call but rather a method definition within a class, and is most certainly not at line 1 column 1)

and

Uncaught SyntaxError: Unexpected end of Input
 at line 1 col 30
t c=0;const l={normal:1,move

It almost seems like Espruino is reading the program as a 30-byte fragment of the full program, and crashing because the resulting syntax within the fragment is invalid.

We know for a fact that the program file itself is intact, as resetting the Bangle and starting the app again works fine (until a few minutes later when it starts throwing the exact same errors again).

For context, the program uses a relatively large amount of RAM, with only less than 300 blocks left out of the usable 2100 blocks, and that's when no function is running and everything is just waiting for events. I don't know exactly how much memory is used at maximum. We have already run into other problems caused by low free memory (which fortunately we have managed to work around) so I hope this is not yet another one of them.

May I ask what causes this, and how we could solve this problem? Thank you.