I have found these bugs, the bug 3 is the most important.
1) In 1701/1702, I have occupied the area of Saint-Petersburg with a russian army, the option "foundation of St-Petersburg" was unlocked. But a small swedish force occupied again this area and I got two options "foundation of St-Petersburg" , one was unlocked and the other was locked.
2) After Denmark left the anti-swedish alliance, you can still build danish garnison units almost everywhere (in Russia, in Poland, ..).
3) After the "Peter rules" option is applied, there are some erroneous elements in the garrison units (example : in Arkhangelsk).. These garrison units don't have any pictures and you can read the words "erroneous elements" in the unit info panel. These units have a zero combat value. They must be the result of an upgrade of the garrison units (an upgrade similar to the upgrade of a russian line infantry regiment).