It seems the `fermata` attribute would cause tempo change in MIDI output, however when combined with changing tempo in `def-score`, the restored level is the last value in the `:tempo` list, which I guess is a bug. the problem can be demonstrated by the following code snippet:

(setf ns
      '((q a4b4d5fs5cs6 mp arp e b5 e5 q fs4g4b4d5a5 arp
           d5)
        (q c3g3d4e4b4 arp h. a5b5d6 #|fermata|#) ;; uncomment this
        ((leg e b2 fs3 s a3 e d4 s_h e4)) ;; the tempo starts here will be whichever is the last
        ((leg e b2 fs3 s a3 e d4 s_h e4)) ;; in the `:tempo' list, which is 164
        ((leg e d4fs4a4 mf marc d4 e4 cs4e4gs4 marc
              cs4 e4 d4fs4cs5 marc d4 leg))
        ((leg e e4 d4fs4a4 marc d4 e4
              cs4e4gs4 marc cs4 d4fs4cs5 marc d4)))) 
(def-score score
           (:key-signature '(d major)
            :time-signature '(4 4)
            :tempo '((q :rit 74 70 1/32 :bars 2)
                     (70 2)
                     (164 3)
                     )
            :layout (list '(:treble notes))
            )
  (notes :omn ns))

 

My current version is 2.2.26652.

 

Thank you for the report. It is a bug indeed.