No typos highlighting for grammar text.tex.latex when using the reopen project option

Prerequisites

[x] Put an X between the brackets on this line if you have done all of the following:
- Reproduced the problem in Safe Mode: https://flight-manual.atom.io/hacking-atom/sections/debugging/#using-safe-mode
- Followed all applicable steps in the debugging guide: https://flight-manual.atom.io/hacking-atom/sections/debugging/
- Checked the FAQs on the message board for common solutions: https://discuss.atom.io/c/faq
- Checked that your issue isn't already filed: https://github.com/issues?utf8=✓&q=is%3Aissue+user%3Aatom
- Checked that there is not already an Atom package that provides the described functionality: https://atom.io/packages

Description

Spell-check does not highlight misspelt words for grammar text.tex.latex when loading .text files using the reopen project option. However, it works as expected if a file is opened directly (e.g., double click). The issue persists on safe mode and there is no error message at any step.

The only setting changed in spell-check is the addition of the grammar text.tex.latex.

Steps to Reproduce

Open atom and reopen a project folder containing latex files, note that spell-check will not highlight misspelt words.
Close atom completely, open a latex file via double-click, open with > atom or terminal, note that spell-check works correctly.

Expected behavior:

Spell-check highlight misspelt words in text files by opening a file directly or using the reopen project option.

Actual behavior:

Spell-check does not highlight misspelt words in text files using the reopen project, only by opening directly.

Reproduces how often:

It is persistent behaviour and happens most of the time, in rare occasions spell-check loads correctly.

Versions

Atom    : 1.56.0
Electron: 9.4.4
Chrome  : 83.0.4103.122
Node    : 12.14.1

Additional Information

The issue was replicated on a fresh install of atom, my .atom folded was renamed to isolate possible configuration conflicts.

Relevant packages installed:

latex : 0.50.2
language-latex  : 1.2.0

atom / spell-check