LaTex Error in combination of MathTex and SurroundingRectangle.

[Igittigitt24]

Description of bug / unexpected behavior

In preparation for SurroundingRectangle() I called MathTex() with several items.
One of them contains an opening brace (the corresponding closing brace comes later on).
But this leads to a Latex Error couple:

ERROR LaTeX compilation error: Missing } inserted.
ERROR Context for error: \begin{align*} \frac{} \end{align*}

Expected behavior

An error should not occur like can be seen in the small example program below, because both open- and close-brace are given!

How to reproduce the issue

Here is an illustrating example (containing both the error version and an (unwanted) error-free version):

from manim import *

class MovingFrameBoxDiv(Scene):

    def construct(self):

        if 1: # try to write            ... = \frac { u'v - uv' } {v^2} 
              # for boxes:                           └─3─┘ └─5─┘
                
            text = MathTex(                    
               r"\left( \frac{u}{v} \right)'", # 0
                "="                          , # 1
               r"\frac {",                     # 2   ⇐ error-stop at opening brace
                "u' v"                       , # 3 *
                "-"                          , # 4
                "u v'"                       , # 5 *
                "} {v^2}",                     # 6   ⇐ closing brace 
            )  # ⇑                                   ⇐ is here!

        else: # instead use unwanted   ... = { u'v - uv' } \frac {1} {v^2}
              # for boxes:                    └─3─┘ └─5─┘
                
            text = MathTex(                    
               r"\left( \frac{u}{v} \right)'", # 0
                "="                          , # 1
               r"\left( \, "                 , # 2         
                "u' v"                       , # 3 *
                "-"                          , # 4
                "u v'"                       , # 5 *
               r"\, \right) \frac{1}{v^2}"   , # 6         
            )
            
        box1 = SurroundingRectangle(text[3], buff = .1)
        box2 = SurroundingRectangle(text[5], buff = .1, color=RED)

        self.play( Write (text) )
        self.play( Create(box1) )
        self.play( TransformFromCopy(box1, box2) )

        self.wait(5)
        
MovingFrameBoxDiv().render(1)

[Igittigitt24]

from manim import *
'''
    This unsatisfying fiddling dirty workarround yields the output ...  
'''

class MovingFrameBoxDiv(Scene):
    def construct(self):

        # ... = \frac { u'v - uv' } {v^2} 
                
        text = MathTex(                    
               r"\left( \frac{u}{v} \right)'", # 0
                "="                          , # 1
               r"\frac {"                      # 2   ⇐ removed commas
                "u' v"                         # 3   ⇐
                "-"                            # 4   ⇐
                "u v'"                         # 5   ⇐
                "} {v^2}",                     # 6 
        )

        box1 = Rectangle(color=YELLOW)
        box2 = Rectangle(color=RED)

        box1.stretch(0.2, dim=0); box1.stretch(0.3, dim=1)
        box2.stretch(0.2, dim=0); box2.stretch(0.3, dim=1)

        box1.shift(0.35*UP + 0.24*RIGHT)
        box2.shift(0.35*UP + 1.52*RIGHT)

        self.play( Write (text), run_time=3 )       ; self.wait(1)                   
        self.play( Create(box1) )                   ; self.wait(1)
        self.play( TransformFromCopy(box1, box2) )  ; self.wait(1)

        self.wait(5)
        
MovingFrameBoxDiv().render(1)

[Igittigitt24]

This is what I expect using SurroundingRectangle:

MovingFrameBoxDiv.mp4