There is nothing you can do to fix this problem unless your software is out of date. When the internal PDF generation capability was added during November 2016, there were many such problems. All known ones were fixed. What version are you running under About Manager?
You are 21 versions behind as of today. Please update and let us know if the problem remains. If it does, I will elevate the issue as a bug for attention. Be sure your numbers do not include spaces. One of your examples suggests they might.
@Gert, your issue is unrelated to @Kristen_Lalin’s. The Euro symbol substitution is a short-term workaround, as you were told earlier, until the underlying problem can be fixed. There has never been any statement that the font-family attribute would ever be supported. Manager supports a restricted set of capabilities.
Updated to Manager 16.12.56 (windows machine) but problem is still there. If number is 100-999 then it will put last number to new line. No spaces inserted.
1000-… then everything is OK.
(same problem with buying invoice and selling invoice)
@lubos, it looks like there is a problem with the PDF generator when quantity numbers are more than 2 digits. But there is something further happening, apparently, because in one instance 4 digits (possibly with a space in there) rendered correctly.