I am assuming you understand that the small-small combo is not advisable, but this still should not occur even in that combo, and I also am assuming that the problem extends beyond that combo, as you said it occurs as you go "toward the 11 in back"

Let's look at what the drive train is doing. The chain is traveling from the chainwheel toward the derailleur pulley as you pedal. The angle between the two is increasing as you move outward on the cassette, and the derailleur is wrapping more chain and therefore the pulley assembly is pivoting. If the chain does not unship when closer to frame centerline then either the alignment of the pulley cage is changing as it rotates or the angle between small cogs and chainwheel is too extreme, so that the chain does not feed on properly. It of course corrects with backpedaling because it is always being fed chain in a straight line from the upper pulley.

If this is new behavior the odds are very high that either the derailleur or the derailleur hanger has been damaged such that the cage is no longer parallel to the bike's vertical centerline. The cage's angle would then change as it rotates. The other cause would be poor chainline - that is the entire freewheel being too far out or chainwheel too far in. that would only occur in a crash that bent the rear triangle or an overhaul that changed either hub or chainwheel distance from the center of the bike. The latter is much less likely to have occurred without you mentioning it and is also less likely to cause the problem without other issues as well.