Unable to change Dimension and Scale values in later frames


I have a strange alignment issue on a human model in blender. A human is standing at a particular location at ‘0’ th frame. The details of the location etc. values are below.


x: 9.8206
y: 55.20318
z: 3.70269

x 0
y 0
z 351.246

x 2.510
y 2.510
z 2.510

x 3.821
y 6.3
z 12.259

I am adding many lipsync animation for this human. LipSync animation is added UPTO “3000” frames. But, this human should be in the same location, rotation, scale etc.

The issue is, i am seeing this human transform property values, there is a slight change happening in ‘Dimention - X : 3.848; Y : 6.29 ; Z : 12.257’ greater than “1000” th frame onwards. I am trying to set back this values to the expected values, but if i change Dimension value to the expected values, then it affects Scale value getting changed slightly. So, i’m unable to set back the Dimension and scale values when it gets changed in Blender Objectmode.

Could someone guide me how to fix this?