When I am using this snippet
{note: preview=yes; insert=no; trim=yes}This is an important note I need people to read{endnote}Something to insert.
I am not getting a preview but the text gets immediately inserted. I verified several times and I am not accidentally pressing ENTER, only the shortcut is typed.
This previously worked as expected. Has an update broken something?
I tested in internal software and Slack. These are tools where previews previously worked.
I also tested w TRY IT OUT and I see no preview.
Hi @Zita_Daniel_Nad Welcome back to the forum! 
I tested this snippet on the Text Blaze Chrome extension from one year ago, and it still inserts this snippet directly without showing the form window.
Are you also using the Chrome extension? Do you remember the last time when this used to behave differently?
You probably used the note in conjunction with a form control last time, which displays a snippet in a popup window first.
Try adding a dummy form control in a hidden note (preview off).
I do not remember when it worked differently. But I know that it did.
Can you clarify what PREVIEW YES is meant to do?
{note} with preview=yes will show the contents of the {note} when a form window is open. But, by itself, {note} with preview=yes will not cause a form window to open.
The form window opens when your snippet has a form field to input into, when one of your {site} commands matches multiple open tabs, and in a few other cases.
As @samliew suggested, adding a form field into the snippet will cause the form window to open.