Bukkit

[What steps will reproduce the problem?]
1. Selling lots of item at a time in a AdminShop.

[What is the expected output? What do you see instead?]
Causes lots of TPS drop, makes time out, and more...

[What version of the plugin are you using? (/csversion), "latest" is not an answer]
3.8.12

[What version of the CraftBukkit are you using? (/version)]
1.8.3-R0.1-SNAPSHOT

[What economy plugin are you using? (iConomy, BOSEconomy, etc? - include version as well)]
iConomy version 7.0

[If the defect involves other plugins, please include their names and versions below]
...

[Do you have an error log of what happened? Check your console, server.log and messages you got through chat]
The log that appears in console is player sells item
[22:12:43 INFO]: [ChestShop] Panics sold 752 Redstone for 75.07 to Titanium Shop at [Minas] 13, 70, 72

This causes lag when says in console.

[Please provide any additional information below.]
I've already tried to increase SHOP_INTERACTION_INTERVAL, it's at 1000 and does the same.

Could you provide a timing log?