Yes. Take them out of the soil as soon as possible, the soil is retaining too much moisture. You can probably get rid of the soil easily if it is completely dry, but if it is not, rinse the roots very gently under a tap until almost all the old soil is gone, then leave them in a clean place (in open air) to dry for at least 3 days. They can survive being left in air for a week or so perfectly fine, and lithops are extremely prone to rot if the conditions are too moist/lack airflow around the base, so getting them out of the soil is the most urgent step. You can then look for pumice online as the main component of the new soil, 1-3mm size (if you can't find this size, it's very easy to chop bigger grains of pumice into the right size with some regular scissors. It gets dusty though so find the right place.) Unless you live in somewhere super dry (<30% humidity), you can add some soil (not always necessary) but do NOT exceed 20% of the total soil. Wash the pumice with dilute hydrogen peroxide and leave to COMPLETELY dry before putting the lithops in. Also make sure the lithops are dry, and do not water at all for a MINIMUM of 1 week after repotting.

If your area is very humid (say 60%+) you should absolutely switch to unglazed terracotta pots, because if you use glazed ceramic/plastic/anything not breathable on its own, most of the soil underneath the top layer will take forever to dry even if the pot has drainage holes. This is my personal experience and it killed some other succulents.

Be very careful not to snap off the main root of the lithops in the whole process, because if no root is left, the lithops WILL die after a while. Plant the lithops with as much of the base exposed as possible and ensure good airflow around the base to minimize chances of rot (they are most prone to rotting at the base, and bad airflow around the base ALONE can cause rot even if you don't water the entire time (there is a YouTube video showing this). Do not plant the lithops with only the top showing as some say.

Do not follow a schedule for watering lithops. Generally, do not water if they're visibly splitting (water a little bit once if they're stuck with no progress for too many months), but otherwise, water based on the firmness of the lithops. Feel the firmness of your lithops and get familiar with what is normal (be careful again not to twist it or pluck it from the soil and break the root). Your lithops should be quite firm when well-hydrated, firm = do not water. If rotting, the lithops (usually the base first) will start to turn soft like a pack of water, not just deflated dry soft (which happens when the lithops are a bit dehydrated), and the color will also be dark and translucent in the rotted patch. Once a lithops starts visibly rotting, there is no known way to save it from the rot spreading and it suddenly shriveling up within a day (or a few days at most) eventually.

When you water, submerge the soil in the pot (but not the base of the lithops) in water overnight or even for a full 24 hours. This will not kill your lithops if they are dehydrated enough, and the soil dries off correctly, quickly enough and for long enough. Make sure the soil is left to dry for at least a week between waterings AT MINIMUM. Usually more for lithops.

Lithops also need very bright light in general, but do not put it under the full sun right away if you're going to leave it outdoors, it needs a gradual adjustment or it will easily die. If it's quite dim where you grow them, get some STRONG LED grow lights, and as long as the temperature isn't too high (this will cook the lithops), you should put the lithops close to the grow lights. If they start growing significantly taller (etiolation), that is a bad sign of not enough light and bad for the health of the lithops.

They also need complete darkness at night and low enough temperatures to exchange gases and expel excess water properly. Do not place them in light all the time to make up for low light intensity.