Hi Cosimo,
We regret for the inconvenience caused.
We were able to reproduce the issue with special characters in Treegrid and we have confirmed this as bug and logged a report on this. Also we have created a
support incident under your account to track the status of this issue.Please log on to our support website to check for further updates.
https://www.syncfusion.com/account/login?ReturnUrl=%2fsupport%2fdirecttrac%2fincidents
Please let us know if you require further assistance on this.
Regards,
Dinesh kumar.N