If suggested edit have been opened via “edit (1)” link under the post body then buttons will be displayed in two rows without a normal alignment:
Same edit opened within review queue displayed correctly:
This happens due to changing working window width. In popup view width is smaller.
Same design issue occurs in Stack Overflow in Russian, but for items opened in review queues because of the longest words in the buttons.
Seems this issue is related to another bug that already fixed.