1. I wrote to you earlier - attach an example. Why ignore?
2. The answer is simple - in Acrobat, the measurement is made on the external side of the lines, taking into account the line thickness.
In AutoCAD, the measurement in the middle of the line does not depend on the thickness.
And Acrobat takes into account the thickness of the line.
If you consider that you use the scale, then this leads to a 0.03