Forum Bug: Signature Horizontal Line bug

I have found a small bug with forums signatures containing a horizontal line and 4 lines of text. The forum will only display 3 lines and the horizontal line, without the prompt to expand the signature, even though it is hiding the fourth line of the signature. My signature currently displays this bug. My signature is intended to look like this:

Code:

I'm not normal. Because normal is stupid. And stupid is normal. | Life has no respawns.
Band Nerds group | Camera mode tutorial | Camera mods: Helicopter Cinematic
Magni: Pentium G630 | GTX 950 | 8GB RAM | WD Blue 1TB - WD Blue 160GB | Windows 10
[HR][/HR]Nadeox1 "testing" | Nadeox1 testing? (again?) | kstamou "Test"

But it lacks the Expand Signature option shown below. When I add a new line after the horizontal line, it adds the Expand Signature option:

Code:

I'm not normal. Because normal is stupid. And stupid is normal. | Life has no respawns.
Band Nerds group | Camera mode tutorial | Camera mods: Helicopter Cinematic
Magni: Pentium G630 | GTX 950 | 8GB RAM | WD Blue 1TB - WD Blue 160GB | Windows 10
[HR][/HR]
Nadeox1 "testing" | Nadeox1 testing? (again?) | kstamou "Test"

However it adds an undesired empty line:

This appears to be a problem with how the forum determines the number of lines to allocate to the signature, ignoring the fact that the horizontal line adds a line to the signature.

 

It does not when immediately followed by text:

Code:

Text above line.
[HR][/HR]Text on same line.

[HR][/HR]
Text on new line.

Text above line.

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Text on same line.

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Text on new line.