To reproduce:

1. Download and open attached "UnityBugReport.zip" project.
2. Build and run to any android or iOS device.
3. Enter some text into the Input Field and press OK.

Expected result: Inputted text is updated in the text gameObject above the input field. Reference to the TouchScreen Keyboard in OnEndEdit event is not lost instantly after closing TouchScreen Keyboard. Reference to keyboard remains when event code is being executed.
Actual result: Text is not updated. After pressing OK on keyboard it is closed and reference to TouchScreen Keyboard is lost in OnEndEdit event. Therefore, there is no way to check TouchScreen Keyboard status in OnEndEdit event.

Reproduced with: 2018.1.0a5, 2017.3.0b10, 2017.2.0p2, 2017.1.2p3, 5.6.4p3, 5.5.5p1.

Devices Under Test:

Google Pixel XL, OS:8.0.0, CPU:arm64-v8a, GPU:Adreno (TM) 530,
Build:google/marlin/marlin:8.0.0/OPR6.170623.012/4283428: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

Samsung SM G928F*, OS:7.0, CPU:arm64-v8a, GPU:Mali-T760,
Build:samsung/zenltexx/zenlte:7.0/NRD90M/G928FXXU3CQG2:user/release-keys

iPod 6th gen iOS10.2.1

Notes: Issue prevents users from getting TouchScreen Keyboard state in OnEndEdit event. The intention is to know if user did exit the keyboard by cancelling the input or validating it by pressing OK. Since the reference to keyboard is lost in that event, there is no way to know what users actions were.