using too much vram

[Uemuet]

lately i get this failure that im going to the limits of my vram and i dont know why,
because i can get only render less frame batches than before and get this.

torch.cuda.OutOfMemoryError: Allocation on device 0 would exceed allowed memory. (out of memory)
Currently allocated : 27.28 GiB
Requested : 22.21 GiB
Device limit : 39.56 GiB
Free (according to CUDA): 20.81 MiB
PyTorch limit (set by user-supplied memory fraction)
: 17179869184.00 GiB

and a month before i could render 400 frames in a high resolution.
My environment is colab pro