the blogger who had a similar experience with his spark CC with $10K CL saw a huge CLI when he logged in one day. Credit line was up from $10K to $80K without requesting it. He asked other heavy users of this CC if they experienced this and he was told to close the card. Apparently, offers like this means one's account has been flagged and there are eyeballs on it.
In OP's case, tread lightly because the signs are there that your account is being watched. It's up to you if you will proceed with your "usual" MS activities but be prepared for consequences.