Steps to replicate the issue (include links if applicable):

1. Inside a template, invoke a module that takes one argument, which is a string with an absurd amount of leading and trailing whitespace. Use an anonymous parameter; do not define this directly in #invoke.
2. Surround this template with <includeonly> tags. Inside <noinclude> tags, transclude the template onto its own page and include the absurd string argument.
3. In a module, capture only the content of said string argument, excluding whitespace, using Regex. I used the capture pattern ^%s*(.+)%s*$ with string.match().
4. Save both template and module, then refresh the template page to see result.

What happens?
Leading whitespace of a string is stripped completely, but trailing whitespace is left untouched.

If this is my input:
Moo

I get this when capturing with Regex:
Moo

Here is what I attempted inside a module:

local p = {}

function p.main(frame)
    local args = frame:getParent().args
    local finalString = 'START-->'

    for _, line in ipairs(args) do
        finalString = finalString..'|'..line:match('^%s*(.+)%s*$')
    end

    finalString = finalString..'<--END'

    return finalString
end

return p

What should have happened instead?
Leading and trailing whitespace should be removed from the string using Regex with string.match(), similar to how mw.text.trim() works.

This should be what I get from the input above:
Moo

This works in a code editor, or using Lua's built-in environment after it's compiled, but it doesn't work on a wiki for some reason.

Software version (skip for WMF-hosted wikis like Wikipedia)
Software

• MediaWiki: 1.39.0
• PHP: 8.0.26 (fpm-fcgi)

Installed extensions

• Scribunto
• TemplateStyles: 1.0 (f09fb72)

Installed libraries

• wikimedia/parsoid: 0.16.0-a21

Other information (browser name/version, screenshots, etc.):
I ran this test on:
Chromium ( Version 110.0.5481.100 (Official Build) (64-bit) )