Previewer glitch scrolling through file when horizontal scroll appears

**Environment:**
- Preview version: Latest (cdn)

**Smartphone (please complete the following information):**
- Device: iPhoneXR
- OS: iOS 12+
- Browser: Safari

**Steps to reproduce the problem:**
1. Open file with different page width (or zoom any other file) to make horizontal scroll appears (at least 5+ pages)
2. Start scroll

**What is the expected behavior? (Screenshots can be helpful here)**
Scrolling is smooth and there is no flashing on screen.

**What went wrong? (Screenshots, console logs, or HAR files can be helpful here)**
Previewer glitch when scrolling.

**Link to application or sample code:**
https://test-box-annotations.herokuapp.com/

**If relevant, link to file (or attach file here)**
https://drive.google.com/open?id=1iSh12uX956X6E7o9ZyzUKU_0nyBL7Pk0

**Expected behavior**
Scrolling is smooth and there is no flashing on screen.

Thank you in advance!

Start by reproducing the issue in the linked test application on an iPhone XR or Safari with the provided file, using a zoom level or page width that creates horizontal scrolling. Inspect the previewer behavior while scrolling through at least five pages and identify the cause of the flashing. Done means scrolling is smooth without visual glitches in this scenario.

Written by the indexing model from the issue text.