Subject offset on the counters

[mattsodoma]

Looks like your subject offset is from counters not being reset between loops. Its possible that grepl is not returning something when there is no match so it isn't resetting a match_a1 value. It seems to work fine as long as you reset these within the loop. I dont know if list is the optimal structure, but seems to work. The issue now, is that you need a contingency in place for when match_a1, a2, or a3 are not found as it errors out on subject 2117. You'll want something with the inverse logic of this, something like if match_a1 does not exist, next, else the code you have.