Looking on the internet deeply has found these results:

is still under repair is the most popular phrase on the web.

is still under repaired 18 results on the web	is still under repair 1102,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
In addition, the VMS is still under development and has never become operational. Your place is still under crime scene investigation. The motivation is still under investigation. It began about thirteen billion years ago... and is still under construction. The precise type of action and data to be collected is still under examination. The elder Piotrovsky is asking... whether the director's telephone is still under surveillance. This matter is still under discussion. Important work in this area is still under way.	It began about thirteen billion years ago... and is still under construction. In addition, the VMS is still under development and has never become operational. The motivation is still under investigation. Your place is still under crime scene investigation. Mechagodzilla is still under repair and is not operational. Important work in this area is still under way. This matter is still under discussion. The elder Piotrovsky is asking... whether the director's telephone is still under surveillance.

is still under repaired

18 results on the web

is still under repair

1102,000 results on the web

More popular!

In addition, the VMS is still under development and has never become operational.
Your place is still under crime scene investigation.
The motivation is still under investigation.
It began about thirteen billion years ago... and is still under construction.
The precise type of action and data to be collected is still under examination.
The elder Piotrovsky is asking... whether the director's telephone is still under surveillance.
This matter is still under discussion.
Important work in this area is still under way.

It began about thirteen billion years ago... and is still under construction.
In addition, the VMS is still under development and has never become operational.
The motivation is still under investigation.
Your place is still under crime scene investigation.
Mechagodzilla is still under repair and is not operational.
Important work in this area is still under way.
This matter is still under discussion.
The elder Piotrovsky is asking... whether the director's telephone is still under surveillance.