The Rams trailed 21-3 at halftime. It went from bad to worse to open the second half when Stefon Diggs caught a 4-yard touchdown pass from Josh Allen with 8:05 remaining in the third quarter.
The Rams have scored 22 unanswered points, though, to draw within 28-25 with most of the fourth quarter to play.
The game turned on a controversial on-field ruling that was upheld on replay. FOX rules analyst Mike Pereira questioned the decision.
Tyler Kroft was called for offensive pass interference, clearly catching a pass from Allen before Rams defensive back John Johnson III wrestled it away on the ground. Officials somehow saw it as an interception.
Rather than a penalty on the Bills, the Rams took over at their own 41.
Rams safety Jordan Fuller (shoulder) won’t return.