City security level fixed at 50 in all civilizations

[iXight]

Hi, the header says it all, security level is fixed at 50 (max) for each civ at turn 169, medieval era. Is this a bug?

 

[axatin]

When the first spies are recruited, city-security is initialized at 50. It then changes gradually each turn.

 

[iXight]

When the first spies are recruited, city-security is initialized at 50. It then changes gradually each turn.

I didn't know that, many thanks!