Steps to reproduce:
1. Select just about any report.  "Balance Sheet" or "Cash Flow"
2. 
3. 


Stack trace:
In /usr/share/gnucash/scm/report.scm:
 429:  5* [gnc:backtrace-if-exception #<procedure #f ()>]
In unknown file:
   ?:  6  (letrec ((dumper #)) (catch (quote ignore) (lambda () #) (lambda # #f)))
In /usr/share/gnucash/guile-modules/gnucash/main.scm:
 158:  7  [catch ignore #<procedure #f ()> #<procedure #f (key . args)>]
In unknown file:
   ?:  8* [#<procedure #f ()>]
In /usr/share/gnucash/guile-modules/gnucash/main.scm:
 161:  9* [lazy-catch #t #<procedure #f ()> #<procedure dumper (key . args)>]
In unknown file:
   ?: 10* [#<procedure #f ()>]
In /usr/share/gnucash/guile-modules/gnucash/main.scm:
 162: 11* [apply #<procedure #f ()> ()]
In unknown file:
   ?: 12  [#<procedure #f ()>]
In /usr/share/gnucash/scm/report.scm:
    ...
 433: 13  (set! html (gnc:report-render-html report #t))
 433: 14* [gnc:report-render-html # #t]
 398: 15  (if (and (not #) (gnc:report-ctext report)) (gnc:report-ctext report) ...)
 406: 16  (let ((template #) (doc #f)) (set! doc (if template # #f)) doc)
 409: 17* (set! doc (if template (let* # # # ...) #f))
 409: 18* (if template (let* # # # ...) #f)
 410: 19  (let* (# # # ...) (gnc:html-document-set-style-sheet! doc stylesheet) ...)
 412: 20* [cash-flow-renderer #]
In unknown file:
   ?: 21  (letrec ((get-option (lambda # #))) (gnc:report-starting reportname) ...)
In /usr/share/gnucash/guile-modules/gnucash/report/cash-flow.scm:
 117: 22  (let* (# # # # ...) (define # #) (define # #) ...)
 144: 23* [gnc:case-exchange-fn pricedb-nearest # #]
In /usr/share/gnucash/scm/commodity-utilities.scm:
 823: 24  (case source-option (# #) (# gnc:exchange-by-pricedb-latest) ...)
/usr/share/gnucash/scm/commodity-utilities.scm:823:3: In procedure memoization
in expression (case source-option (# #) ...
):
/usr/share/gnucash/scm/commodity-utilities.scm:823:3: In file
"/usr/share/gnucash/scm/commodity-utilities.scm", line 822:
Duplicate case label quote in expression (case source-option ((quote
weighted-average) (gnc:make-exchange-function (gnc:ma
ke-exchange-alist report-currency to-date-tp))) ((quote pricedb-latest)
gnc:exchange-by-pricedb-latest) ((quote pricedb-ne
arest) (lambda (foreign domestic) (gnc:exchange-by-pricedb-nearest foreign
domestic to-date-tp))) (#@else (gnc:warn "gnc:c
ase-exchange-fn: bad price-source value"))).


Other information:
To get gnucash to start without getting into the same state, I have to edit
~/.gnucash/books/<book> to remove the reference to the report page.

The bug is filed as Fedora Devel
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=191556

Using guile-1.8.0