For the exact meaning of this passage, there are two main options: 1) The augurs are travelling to Ašramma, a place different from the location where the letter is being written, and are expected to return after this trip; in this case the two actions are sequential. This interpretation is quite linear, since the detail that the augurs are heading to Ašramma might not have been known to the receivers of the letter. 2) Alternatively, Ašramma is the same place where the letter is being written; if so, then the second
kuitman introduces a parenthetic statement, replicating the same meaning: “until the augurs arrive at Ašramma - until they come back - (…)”.
=ma could thus be seen here as a marker of concurrent action (particularly with
kuitman;
Hoffner H.A. – Melchert H.C. 2008a 398, §29.35); the repetition of
kuitman, however, is peculiar.