The Yerushalmi (end of perek 1 of Bikkurim) discusses a machlokes Tana'im between the Chachamim and Rabbi Meir whether in a sale of trees the land they grow on is included or whether the land remains in the possession of the seller (this is also found in the Bavli in Baba Basra). Everyone agrees that the purchase of 3 or more trees includes land; however, the Chachamim hold that the sale of 2 trees (and R' Meir holds the same by the sale of 1 tree) is a safeik l'halacha. Therefore, according to the Yerushalmi, the purchaser of 2 trees is obligated to bring bikkurim, but cannot recite the parsha of bikkurim as he cannot properly refer to "admascha", his land, as the ownership status remains in question. Achronim are bothered by this halacha - why should we treat the ownership of land as a situation of "doubt" and force the buyer to bring bikkurim? The principle of chezkas marei kammah, the assumption that until proven otherwise properly remains the possession of its original owner, would seem to dictate that in any case of doubt, the land is assumed to be in the possession of the seller. The famous sugya in Bava Metziya 6 of “takfo kohein” teaches that since a kohein cannot "grab" a safeik bechor from its owner, the owner must treat that animal as his own and it is obligated in ma'aser beheima. In our case, if there is any obligation of bikkurim, it should rest on the seller who has a definite ownership stake until proven otherwise! The Ohr Sameiach (Bikkurim 2:13) is forced by this question to reinterpret the entire sugya. Without rehashing the intricate details, we actually touched on an approach to deal with this issue. While it is true that chezkas marei kammah resolves questions of safeik ownership, here the issue is not a classic safeik caused by a monetary dispute where Reuvain says X and Shimon argues Y. Here the halacha itself has created the safeik – it is a safeik in din, not a safeik in metziyus. And while the Ohr Sameich (consistant with what we noted previously in the Meshech Chochma!) does not distinguish, many achronim do argue that with respect to a safeik in din, chezkas marei kammah does not suffice as a resolution.
There is much written on this topic, especially notable being the shtickel in my brother-in-law’s sefer on Baba Basra, “Bigdei Sheish”, siman 27, which elaborates on R’ Shimon Shkop’s approach to the sugya. If you don’t have a copy, contact the author.