Looks like other people are onto the same thing - alignment.
Especially if this is threaded code, what's probably happened is something (likely with some sort of locking primitive) that fit on one cache-line, now straddles two. The reverse is also possible where two items were landing on different cache lines and are now creating a false sharing problem.
It's likely a global and likely in the .bss (which comes immediately after .data, which is why it has alignment troubles when static strings change). It's usually pretty easy to binary search your way to the problematic module and variable.
Especially if this is threaded code, what's probably happened is something (likely with some sort of locking primitive) that fit on one cache-line, now straddles two. The reverse is also possible where two items were landing on different cache lines and are now creating a false sharing problem.
It's likely a global and likely in the .bss (which comes immediately after .data, which is why it has alignment troubles when static strings change). It's usually pretty easy to binary search your way to the problematic module and variable.