Checkboxes uncheck when I close PDFs character sheets

[Hemenyatta]

Describe the bug
I'm playing with Sandbox System Builder and when I link a checkbox from the system to a checkbox from my fillable character sheet it works but when I close the page and reopen it the boxes are unchecked even though I left the page in them leaving checked. If I make a checkbox add 2 to an attribute it works and when I quit and reopen the pdf the +2 is still there but the box is unchecked.

To Reproduce
Steps to reproduce the behavior:

1. Launch a Sandbox System Builder game and add a form fillable PDF character sheet with some checkboxes.
2. Make a checkbox property that add +2 to an attribute like HPs with this command on the attribute property : if[@{checkbox_name}:true,2,0]
3. In your form fillable PDF name a checkbox like that : data.attributes.checkbox_name.value. Save the PDF and reload foundry with F5
4. Now you can see when you check the box on your PDF it adds 2 to the HPs attribute and when it's unchecked it removes 2. But if you check the box and leave the PDF and re-open it, the +2 are still here but the box is unchecked.

Expected behavior
When you re-open it after you left the page with the checkbox on, the checkboxes are still on and not off

Screenshots
Is not a screenshot beacause you'll see nothing on a screenshot but it's a video from my youtube : https://www.youtube.com/watch?v=220ruv-adPg

Version Information:

• FoundryVTT 9.269
• PDFoundry 0.9.5
• Activated Systems & Modules w/ Versions : Sandbox System Builder : 0.12.4