/say - Invalid command syntax

1.2.0.7

Summary: Typing the following text command results in "Invalid command syntax":
/say §6(Test) §7Follow green [1] block markers.

For some reason it thinks [1] is a parameter and returns a "Invalid command syntax" error. I reported this issue on Slack and it was confirmed by @fvadillo

It happens for both command blocks and text chat.

Impact:

What is the impact to players/partners if we don't fix? Our map is broken. But we can easily resolve it by replacing [1] with (1) and similar. It's not a huge issue.

Repro Steps:
1. Type /say §6(Test) §7Follow green [1] block markers.
2.
3.
Observed Results: Invalid command syntax
Expected Results: (Test) Follow green [1] block markers.
Screenshots/Videos attached: Yes/No
Notes: