Hi Domenico,
We are very sorry for the delay caused in getting back to you. we have analyzed the stack trace posted in the last update and we suspect this could be a defect. So we request you to open a new direct-trac incident with a simple issue reproducing sample for further follow up on this issue.
Direct-Trac Link:
https://www.syncfusion.com/account/login?ReturnUrl=%2fsupport%2fdirecttrac%2fincidentsPlease, let us know if you need any clarifications.
Thanks,
Lokesh.