Items dont shrink properly

I didnt find same problem on forum, so sorry if i overlooked it.

How this should work: if item in main hand and player right clicked with it it supposed to send message in action bar and then be shrinked by 1.
Problem is that item doesnt shrink when right clicked if only in main hand. It does player have item in both hands.

Here is screenshot of script: https://yandex.ru/images/search?cbir_id=2332506%2FLhXT6tn_72L_unsfiAgXnQ1978&rpt=imageview&url=https%3A%2F%2Favatars.mds.yandex.net%2Fget-images-cbir%2F2332506%2FLhXT6tn_72L_unsfiAgXnQ1978%2Forig

Maybe video can make this question clearer, and prepare your ears, i didnt work hard on this vid: https://youtu.be/aUB-NSh_LDU