To circle back on this, no evidence of mass surrender so far. Russian troops are reportedly inside Liman, and there are unconfirmed claims that Ukrainian forces in the town are cut off. This may lead to mass surrender in the future, but it doesn't look like this has already happened.Unconfirmed: There are several pro-russian sources claiming that Russia has taken Liman or at least the part north of the railway and that between 300 and 600 Ucranian soldiers have surrendered. We need more independent reporting to confirm or disprove this claim.
EDIT: Ukranian sources also talk about russians storming liman: