Unexpected INI parsing of keys with colon

[Zash]

Describe the bug
I tried the new INI support on some random files I had around my system and found that a key like this:key = value gets parsed in a way I did not expect. Notably some Mercurial config files containing lines like default:pushurl = ssh://hg@hg.example.org/repo/

Version of yq: 4.46.1
Operating system: linux
Installed via: binary release

Input INI
Concise yaml document(s) (as simple as possible to show the bug, please keep it to 10 lines or less)
data1.ini:

[this:section]
this:line = should really work

yq --input-format ini --output-format json data1.ini

Actual behavior

{
  "this:section": {
    "this": "line = should really work"
  }
}

Expected behavior

{
  "this:section": {
    "this:line" : "should really work"
  }
}

Additional context
I'm not actually sure if INI has a specification and if so, what it says about this.