UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:58.0) Gecko/20100101 Firefox/58.0

Steps to reproduce the problem:
Textbox with onKeyPress handler to check if a tab was inputted.
Using a bar code scanner to input serial numbers into the textbox.
The bar code scanner acts as a keyboard, but inserts text very quickly.

What is the expected behavior?

What went wrong?
An example serial number is: 1234-1234A

Occasionally, the input to the textbox will be one of the following:

1234_!@#$A
1234-!@#$A
1234-1@#$A
1234-12#$A
1234-123$A

The bar code scanner enters the following keys presses:

1234-1234<shift>A</shift>

It seems the shift gets processed earlier then it should be. This behavior is not reproducible in other web browsers or applications.

Was able to reproduce this issue on two different Windows machines, both Windows 10. I believe at least one has had the 1709 update.

The issue is definitely timing related, the second PC this was tested on I believe runs an Atom or other low spec CPU, when the behavior is seen, the entire string was shifted so, "!@#$_!@#$A"

Some bar codes are combined bar codes which are the following format.

1234-1234A;1234-1234A

when when the issue occurs is inputted similar to the following:

1234-!@#$A;1234-1234A

It seems after the capital 'A' the shift is unpressed correctly.

Did this work before? N/A 

Chrome version:   Channel: stable
OS Version: 10.0
Flash Version: Shockwave Flash 28.0 r0