I found this page on Felix Just’s website that details all the changes, shifts, and errors in the 1998 Lectionary as compared to the earlier edition. The author also comments on each discontinuity, citing this for the 18th Ordinary Sunday of cycle C:
OLM81 chooses different Psalm
Psalm 90 fits better thematically
I’d agree, but I wonder about the real intent of the committee on this one. Psalm 95 isn’t bad.