they had uneven divisions (2 with 5 teams and one with 4). To make the schedule work, they had the last place teams in the 5-team divisions play twice the following season. So we played them twice in 1979 as well, since we were both last in 1978. In 1980, the Cards and Lions played twice.
In a previous BBI thread, I listed all the occurrences of this - for example, the 2 games vs DET in 1988.
I believe this went away when Carolina and Jacksonville were added.
1979 vs TB
1981 vs GB
1984 vs TB
1988 vs DET
Yes