For some terrain generation values, swamps occasionally generate surrounded by deserts. This seems out of place, as one would expect some other terrain to generate here. I think the terrain should be something else that's dry and flat (high Temperature, high Erosion).

Sample affected values from seed 5116735402577285868:
x:-17232 z:-5736 (swamp) C0.402 E0.660 T0.742 H-0.026 W0.240 | (nearby desert) C0.276 E0.672 T0.757 H-0.150 W0.403
x:-13348 z:8104 (swamp) C0.219 E0.623 T0.753 H0.021 W1.157 | (nearby desert) C0.214 E0.627 T0.752 H-0.012 W0.894
x:5288 z:7832 (swamp) C0.149 E0.746 T0.640 H0.328 W0.272 | (nearby desert) C0.274 E0.840 T0.606 H0.234 W-0.392
x:-13856 z:520 (swamp) C0.057 E0.623 T0.578 H0.296 W0.032 | (nearby desert) C0.113 E0.591 T0.588 H0.241 W-0.436

All these have a high E (erosion) value around 0.7, and a high T (temperature) value around 0.6.

Related issue: MC-237621.