ob-scheme haunted source code block?

[Joost Kremers <joostkremers@fastmail.fm>]

Hi list,

I've been learning some Scheme recently and decided to use Org 
mode and babel so I could document my progress, keep notes, etc. 
together with the code I write. I also installed the geiser 
package to work with Scheme source files directly. 

This all worked perfectly, until I made the (apparent) mistake of 
typing =C-c C-c= on an expression while editing a source code 
block. That is, I had pressed =C-c '= in an Org buffer on a source 
block and in the editing buffer that popped up, I hit =C-c C-c= 
(bound to =geiser-eval-definition=) on a particular function (well 
procedure...) definition.

From that moment on, that particular procedure definition seems 
haunted. Whenever I evaluate a source block containing it from 
within an Org file, the associated REPL is doomed. It takes about 
30 seconds for the evaluation to complete, during which time Emacs 
seems to hang (no CPU activity, just waiting). Any further 
interaction with the REPL from that point on, either from other 
source blocks in the same file (all source blocks in it use the 
same session) or in the REPL buffer directly, causes the same 
hang.

I can `C-g` out of the hang, but this doesn't solve much because 
any further interaction causes the same hang. 

Putting the relevant procedure definition in a Scheme source file 
and evaluating that (within Emacs, through geiser) is 
unproblematic, so the code itself is not to blame.

The weirdest thing about this is that the problem is persistent. I 
restarted Emacs and in my desperation even rebooted the computer, 
but to no avail.

Does anyone have any idea what might be going on? I rgrepped 
through my =.emacs.d= directory to see if the relevant procedure 
name turns up anywhere but found nothing. I'm not really sure 
where to look beyond that.

Versions:

IELM> emacs-version
"26.3"
IELM> org-version
"9.3.1"

TIA

Joost

-- 
Joost Kremers
Life has its moments