I had this problem in CS3 and it was totally random. I had to double check everything I saved to be sure it was the proper size. I'm now on 5 and have had this same problem randomly happen. I never did find a solution, I just had to be aware of which sides the extra pixels appeared on and then open that png or jpeg or bmp in Photoshop to resize and resave it. Not much of an answer, but I feel your pain.
But I didnt faced such problem with Adobe ILL. CS4
Shouldn't really happen, but make sure you align everything properly with the pixel grid and don't use fractional values on effects such as drop shadows. AI's point/ inch centric math may simply produce wrong rounding results and extend the images to accommodate what it thinks are valid pixels...
I have looked all the option .... alignment, pixel grid , not frictional value ..... But still 1px difference.
Now I have switched back to CS 4. For while till problem not solved.
But there is issue. One more thing I am using Windows 7.
I'm seeing this as well. Doesn't happen for the default artboard, but if you add a new one it shows up when exporting.
I got the same problem and i found the below link. I think that is the reason~
We are pleased to inform you that your request is available in the latest release of Illustrator version 22.0.
Visit your Adobe Creative Cloud Application and update. If you do not see an update on the application please check for update from the flyout options on the application after clicking on three vertical dots. For step by step process please visit: https://helpx.adobe.com/in/creative-cloud/help/download-install-app.html#Checkforupdates
Ashutosh Chaturvedi | Sr. Quality Engineering Manager – Illustrator
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