Steps to reproduce:

1) Download attached project 'ScrollRectJitterRepro.zip' and open in Unity
2) Build and run 'ReproScene' on a device
3) Touch button and drag it around the scene (there will be no jitter as expected)
4) Touch the screen with another finger(without releasing the first one)
5) Release second finger from the screen(first one still should be touching the screen)
Observe: Button will start jitter

Expected result: After releasing 2nd finger button position should be controlled by 1st finger without jitter
Actual result: After releasing 2nd finger Scroll View returns 1st finger position and starting position of this button(when application launched), which causes jitter

Reproduced with:
5.3.7p4, 5.4.5p1, 5.5.3f1, 5.6.0f3, 2017.0a6

DUT:
Verizon SM G930V (Galaxy S7 Verizon), OS:6.0.1, CPU:arm64-v8a, GPU:Adreno (TM) 530, Build:Verizon/heroqltevzw/heroqltevzw:6.0.1/MMB29M/G930VVRU2APG3:user/release-keys

Samsung SM G925F (Galaxy S6 Edge), OS:6.0.1, CPU:arm64-v8a, GPU:Mali-T760, Build:samsung/zeroltexx/zerolte:6.0.1/MMB29K/G925FXXU5DQA7:user/release-keys

iPhone 6 iOS 10.2.1