Dynamic changes on other sounds from the mixer

Hi. I've been running into some odd problems in the pieces I'm making regarding the strings. I don't like the default sound for strings in the mixer, so i usually set them to "Strings Fast." But I've noticed that crescendos and decrescendos on single/tied notes don't work for these sounds. Only for the default sounds in the mixer. I wrote a test score to see if this was true, and it is for me. I'm not sure if this is a bug or intentional, and there's an easy way to fix it, but I'd appreciate any advice on why it isn't working for me. The test file is down below.