Are the Type of Conjugation and Stress Related in the Mari Language?

The question about the Mari stress was the discussion's subject from 1775 (the year of the creating of the first grammar). In the modern Mari language, the type of stress depends on the dialect. Analyzing these data, O.A. Sergeev comes to the following conclusions that in all two-syllable names, the stress in the manuscripts corresponded to modern dialects. However, the analysis of the verbal forms in the first books, which are availible of lingvodoc.ispras.ru shows that in the XIX century their stress had certain systemic differences from modern dialects. Two books were analysed: A. Albinsky's grammar of the Hill Mari language, published in 1837 and a manuscript translation of the Gospel of Matthew into the Vyatka Northwest dialect of the Mari language, created in 1821. In both books, it was discovered that in the 3rd person singular and plural of the present and past tenses the placement of the stress depends on the type of conjugation, but there are some duplicate forms.