Custom codes using a colon not working

[Ybother-antecessor]

I'm trying to add custom shortcuts that are divided into groups for easy reference. I'm trying to use a letter-colon-letter combination so the first letter is the category and the second is the specific entry (e.g. <s><:><1> would produce "Section 1").
However, as soon as I type the first letter, the last item listed in the file for that section is sent. The Sequences window shows the sequence with just the first letter and nothing more.

The file used

Sample output: