Export to pdf Unicode problem

I’m having the following problem: when I try to export a .ods file to .pdf on Libreoffice Calc, I use some Unicode characters. Most of the time they appear in the pdf just fine, but in some cases they are all replaced (but only visually, because if I copy and paste it somewhere, it pastes the correct character) by a different symbol.

I started testing some of the inputs and realized the character ▲ (U+25B2; triangle), when placed before any of the other symbols (characters like ★star and ♪musical note) is what’s causing the problem.

I have no idea how could this happen, or how could I fix it. Any suggestions?

By the way, I don’t know the Unicode of the character that is used to replace the other characters, but I captured an image of it:
Unknown Character

Here are the pdf files. It’s from a ranking that I keep.
The first one is ok, without triangles: OK

The second is the same file with a ▲ character at the cell A4 on the .ods file: Not OK