Does this issue occur when all extensions are disabled?: Yes

• VS Code Version: 1.61.2 (I've seen this before this version)
• OS Version: MacOS Big Sur

Steps to Reproduce:

0. Enable editor.tabCompletion
1. Create a typescript file like this:

if (true)
{
let c = 1;
let d = 1;
}

2. Select from just after c to just after d.
3. Hit tab to try to indent

The result is this:

if (true)
{
let c = 1;
let do {
	
} while (condition); = 1;
}

This seems to trigger completions. Other example are:

Select from after c to after e in let d

if (true)
{
let c = 1;
lengtht d = 1;
}

Select from after c to end of next line

if (true)
{
let cc
}

Note that this seems to depend on what your recent completions are. For example, that last one will become let cconsole if the last auto-complete you accepted was console.