Limiting size of scripts – PB Docs 2021

There is an internal limit on the size of compiled Pcode on any
script. Pcode is the interpreted language into which scripts are
compiled. A script that exceeds this limit can be compiled
successfully, but the error “Maximum script size exceeded” displays
when you attempt to save the script. Note that the amount of Pcode
generated from a given script is not directly proportional to the
number of lines of code, so you might encounter this error in a script
with 1200 lines of code, but not in a script with 1500 lines of code.
To avoid receiving this error, move code to functions that you post or
trigger in the event script.