Setting the thousands separator to a period still seems to be problematic for our users in various ways. IN this case, when the thousands separator is a period and the decimal separator is a comma, the goal doesn't save correctly.
The amount should never change upon save.
The goal amount changes after saving the form when the thousands separator is set to a period.
Also, when XDebug is on, you should see this PHP warning as well:
Notice: A non well formed numeric value encountered in ...\wp-content\plugins\give\includes\formatting.php on line 113
https://github.com/WordImpress/Give/issues/1981
Reopening since @mehul0810 found a bug:

This happens when currency is setup like so:

@DevinWalker
Found Another bug
please see the video http://screencast-o-matic.com/watch/cbQirwIQHv
Another Bug in the dashboard page of All Forms
Step to reproduce the issues
Step 1-> Add Some form and donation to it
Step 2 -> Change thousand separate to anything you like
Step 3 -> Now view the All form page
Places where you will find the same
1> All Forms
2> Form single page

@DevinWalker
When setting Thousands Separator as empty it adding a space with the Amount

Is this an issue?
Another Bug in the dashboard page of All Forms
-> Working Fine ( No need to do anything to it )
When setting Thousands Separator as empty it adding a space with the Amount
->we support space as thousand separator as some number system have that
Just tested this, looks really solid guys. Great work!
Most helpful comment
Just tested this, looks really solid guys. Great work!