via Sports Medicine Research
Quick link to research review by SMR. They conclude since joint contractures happen with and without injury, then low level joint mobilizations may be needed during rehab to lower the level of myofibroblast expression. This explains why some studies show that frozen shoulder responds better to lighter shoulder mobs.
Clinically, I find most painful and non-painful restricted joints respond much better to STM/IASTM and then only joint mobilizations if needed. Once you test passive accessory motion and end feels, perform the STM, then retest the end feel and PAM, joint mobilization is often no longer indicated due to the increase in ROM and end feels changing from hard to firm.