This is usually related to the shell stops, which are in the lower inside walls of the receiver.
If the stops are badly worn, bent, broken, impacted with old fouling, or not staked in place, you may have this problem.
Note that the stops are supposed to be tightly staked in place, and not removed unless they're being replaced.
Note also that staking requires a special staking tool.
Here's an exploded view of the 870. The shell stops are parts 33 and 34.
Press the stops against the receiver walls to test for free movement and plenty of spring tension.
If they're sticky, use a gun scrubber spray to clean the back side by spraying the cleaner behind the stops, dry then spray in a lubricant. (Keep the cleaner off the wood).
If this doesn't correct the problem, either take it to a gunsmith or send it in to Remington for repair.