There's a curious dot both on page 361 of the Gregorian Missal and also on the corresponding page in the Liber Usualis. (Pardon me, if this has been discussed before.)

Look at the word "intra-re" and then look at "su-am" on the following line. The melody is quite similar. For "su-am" there is a dot after the punctum and before the porrectus. For "intra-re", however, there is no room for the dot between the neums and instead the dot is printed above the staff.

I presume the dot should be observed in both cases. Is the dot printed above necessitated by the sacrosanct spacing of the Vatican edition?