Function command returns wrong number of commands executed for embedded functions

As the title says, Function command returns wrong number of commands executed for embedded functions.

As far as I see, this wrong number of command is considered by the maxCommandChainLength game rule.

A data pack to replicate this issue is available in the attachment section here. (dp.zip)

Example: Given two functions:

liach:output

function liach:output/do

liach:output/do

say Expected to have 2 commands ran in the function liach:output

Execution result of liach:output (Looks wrong)

[liach] Expected to have 2 commands ran in the function liach:output
Executed 3 commands from function 'liach:output'

Execution result of liach:output/do (Looks right)

[liach] Expected to have 2 commands ran in the function liach:output
Executed 1 commands from function 'liach:output/do'

What I expect for execution result of liach:output

[liach] Expected to have 2 commands ran in the function liach:output
Executed 2 commands from function 'liach:output'

The data pack containing these 2 functions is attached below (note that there is a few unrelated functions for testing other bugs)

I am working on a solution that fixes this bug, MC-143266, MC-143269, and MC-126946 at the same time. Will update when I get progress.