There is a disagreement between the molecular weight of the literature check and the specification, why are there several molecular weights for the same indicator?

Because the molecular weight of the same protein may not be the same in different kinds of cells due to different post-transcriptional shears and post-translational modifications, such as glycosylation, ubiquitination, etc. In addition, the molecular weights of different isoforms of proteins can be found on the official website of the protein, Uniprot, and the molecular weights of different isoforms of proteins can be found to be different. Therefore, the molecular weights found in the literature may differ from the molecular weights of the antibodies in the manual. (You can check more literature to confirm the molecular weight of the target protein in the target sample).