When we print an invoice or job card and the page shrinks. It is because there is a line in there that cannot fit on the width of the area that is is allocated to.
Please check the following...
1. Long email field or address field
2. White spaces. Sometimes, users forget that they might have been pressing the spacebar and create a line with very long continuous spacing characters. this creates a line that is very long (even though not visible to our eyes). Please edit and see if there is a line like that.
If you are not sure, please contact our support team.