How to reproduce:
1. Open the attached "ResourceFreeze" project
2. Deploy the scene "Main" on Android device (File --> Build & Run)
3. Use logcat to view debugged resource loading time, or connect your device to Console via Connected Player tab
4. Press "Load" on your device to load resources with Resources.Load
5. Observe resource loading time. Its outputted as "Resources.Load BoysClothes and Bodies: xxxx miliseconds"

Result: Resource loading time is approximately 30 times bigger on later versions compared to 2017.2.0a4 (with these two particular blend files)

Regression introduced in - 2017.2.0b1
Reproducible with - 2018.2.0a1, 2018.1.0a7, 2017.3.1p1, 2017.2.1p4, 2017.2.0b1
Not reproducible with - 2017.2.0a4

BY DESIGN - In 2017.2.0b1, "Compression mode" dropdown in Build window was introduced, In alpha, there was no switch, but LZ4 was enabled by default. In b1, the project gets "None" as the default compression method and loads resources slower, but you can always choose LZ4 in "Compression mode" dropdown.

DUT:

Reproducible with:
Google Pixel 2 XL, OS:8.1.0, CPU:arm64-v8a, GPU:Adreno (TM) 540, Build:google/taimen/taimen:8.1.0/OPM1.171019.013/4474084:user/release-keys
Samsung SM G950F, OS:7.0, CPU:arm64-v8a, GPU:Mali-G71, Build:samsung/dreamltexx/dreamlte:7.0/NRD90M/G950FXXU1AQEB:user/release-keys
Samsung SM G903F*, OS:6.0.1, CPU:armeabi-v7a, GPU:Mali-T720, Build:samsung/s5neoltexx/s5neolte:6.0.1/MMB29K/G903FXXU1BQC1:user/release-keys