There is a line

var t = ['19: 38: 50.358 ']

How can I explicitly specify in the code that this string is written to the Google Sheets cell in the format 7:38:50 PM?

I will clarify what is needed for the string 't' to fall into the cell, but there it is defined as time. I have a weird problem, when I run the script from the script editor, sheets defines these cells as time (7:38:50 PM), but when I run the script from the menu button I created, the lines are written right as they are (19: 38: 50.358), and then it is impossible to build a graph with a certain time step. From the script editor and from the menu button, exactly the same function is launched, nothing more. Ex: https://docs.google.com/spreadsheets/d/1zvKDnlzG75yuCq-m-0OWLmCJTxGJugLRJ509tTLhf2o/edit?usp=sharing EX2: https://docs.google.com/spreadsheets/d/10oFExu5lT5y0vRKsNL11wJV_ZyvqOOG-mANEJSv-dhg/edit?usp=sharing