Eclipse plugin: Code commenting (CTRL-/) broken for lines which already have comment

In the Monkey C editor, if you select only lines which have trailing single-line comments and press CTRL-/ to comment the whole lines, the comment markers are incorrectly removed, producing invalid code that won't build. Pressing CTRL-/ a second time would normally restore your original code, but in this case of course it won't.

I verified that this works as expected for C, Java and JS files in Eclipse.

Environment:
Windows 10
Eclipse 2018-09 (4.9.0)
CIQ Plugin 3.0.6 (latest)
CIQ SDK 3.0.7

Test data:
System.println("line 1");
x = 42; // line 2
System.println("But what's the question?"); // line 3
System.println("line 4");

Test Case Summary / Expected Behaviour:
After selecting some code and pressing CTRL-/ twice, the code should be unchanged.

Test case 1:
(select mix of lines with/without comments)
1a) Select all lines
1b) or Select line 1-3
1c) or Select line 2-4
2) Press CTRL-/ twice

Result: PASS
System.println("line 1");
x = 42; // line 2
System.println("But what's the question?"); // line 3
System.println("line 4");


Test case 2:
(select only lines with comments)
1) Select lines 2-3
2) Press CTRL-/ twice

Result: FAIL
System.println("line 1");
//x = 42; line 2
//System.println("But what's the question?"); line 3
System.println("line 4");

Now if you try to uncomment lines 2 and 3, you've got invalid code that doesn't build. Or if you had only pressed CTRL-/ once in the first place.

Test case 3
Repeat test case 2, but only select line 2. Similar failed result.

Test case 4
Repeat test case 2, but only select line 3. Similar failed result.