It would be interesting to know where is your source to say that Agrippina changed the way temps lié were made. In 1899, way before Agrippina started teaching, Alexander Gorsky wrote a manual of Stepanov's notation together with a series of class exercises for beginners (only in russian). In the latter, he wrote an example of temps lié, which is done the way Vaganova always did (with a demi-plié in V position, then opening the leg and stepping onto it). I have not found older references to temps lié, though Lyubov Blok points that older "demi-coupé" exercises in early 19 c. ballet classes were similar to Vaganova's temps lié (Klassicheskiy tanets istoriya i sovremennost, 1987, page 191).
It would be interesting to know where is your source to say that Agrippina changed the way temps lié were made. In 1899, way before Agrippina started teaching, Alexander Gorsky wrote a manual of Stepanov's notation together with a series of class exercises for beginners (only in russian). In the latter, he wrote an example of temps lié, which is done the way Vaganova always did (with a demi-plié in V position, then opening the leg and stepping onto it).
I have not found older references to temps lié, though Lyubov Blok points that older "demi-coupé" exercises in early 19 c. ballet classes were similar to Vaganova's temps lié (Klassicheskiy tanets istoriya i sovremennost, 1987, page 191).