"Invalid status transition" error when attempting to update a ticket

[Tiber_S9]

"Invalid status transition" error when attempting to update a ticket. The issue has been observed for the reporter accounts.

Please note that the issue occurs only when using the Modern UI mode.

[atrol]

MantisBT does not offer a "Modern UI mode".
You might use a non-standard MantisBT offer that provides such a setting.
Please contact the support of the vendor (might be MantisHhub) or the author of a plugin if you should use a 3rd party plugin to get another UI.