Tunnel lifecycle not enabled in the region: can't modify site-to-site VPN tunnel anymore. Web interface bug?

Dear all, Today I had the necessity to modify the "Pre-shared key" to turn-off one of the two tunnels of my site-to-site VPN for debugging reasons. I did it many times in the past but today I got the following error: "There was an error modifying VPN tunnel options. Tunnel Lifecycle is not enabled in the region".

It seems to be a bug because in my (eu-south-1) the "Tunnel Lifecycle" is not available but the "Tunnel maintenance" group and consequently the "Tunnel endpoint lifecycle control" checkbox is appearing in the page. I'm not sure it was there in the past.

Please consider that I didn't touched those options in the interface and even if I try to "Turn on" the option I got the same error. It seems to be a bug of the interface.

Could you help me in some way?

Thanks in advance Francesco