Problem "firamath" und "degreeCelsius"

kalibrierschein/kalibrierschein.cls

@@ -40,6 +40,7 @@ textwidth=489bp,
 textheight=669bp,
 top=85bp,
 headsep=0bp,
+head=12.85pt,%???
 footskip=0bp,
 ]{geometry}
 

kalibrierschein/siunitx-PTB.sty

@@ -41,7 +41,13 @@
   ,tight-spacing = false
   ,separate-uncertainty
   %%%,inter-unit-product = \ensuremath{{}\cdot{}}
-}%
+  % weil default ( {}^{\circ} ) manchmal problematisch ("firamath"!?) 
+  ,text-degree = \textdegree
+  ,math-degree = \textdegree  
+  ,math-celsius = \textdegree\text{C}
+  ,text-celsius = \textdegree\text{C}
+}%     
+
 %%%}
 \AtBeginDocument{
   \sisetup{%