[Koha] Going back to Results from a record doesn't always work

[Elaine Bradtke]

I'm hoping  someone else has seen this, or even better, knows how to fix it.
I think it happened somewhere in the upgrade to 20 (we're on 20.05 but I'm
not sure if was going on during the earlier version of 20, as our small
staff has been cycling on and off furlough and I've only recently gotten a
detailed enough description of the problem to reproduce it).
The problem *only* happens in the staff interface, and *only for certain
records. * I haven't spotted the pattern yet.

With a list of search results, clicking on a title takes us to the bib
record as expected, but when we click results to go back to the list, we
get a blank results page. No error message, just no titles listed.
If we sort the results list, the titles appear.
As I said above, it only happens to certain records, which leads me to
suspect there's a problem in the MARC somewhere.  Experimenting with one of
them, I've tried the following:
1) Checked the record in MarcEdit - it didn't flag up any problems.
2) Replaced the offending record with a Z39.50 download from LC
3) Deleted the record and re-catalogued it using a template that we have.
4) Catalogued it completely from scratch - without a template  (the
template has the same problem!).

No change.  We still get the blank results page.

Here are two records, volume 1 and volume 2 of a pair published and
catalogued in different years. The first was produced as part of a data
conversion project, the second one was catalogued in Koha.  Though that
*doesn't* seem to be the defining difference.
In the first record, the link back to the results list doesn't work.  In
the second one it does.
=LDR  01007nam a22002651a 4500
=001  04068
=003  UkLoVW
=005  20200914194455.0
=008  121030s1996\\\\stk\\\\gr\\\\\001\0\eng\d
=020  \\$a1897976119
=040  \\$aUkLoVW$beng$cUkLoVW
=099  \\$aMPS 60 (22)
=245  10$aAndrew Crawfurd's collection of ballads and songs /$cedited by E.
B. Lyle.$bVolume 2
=260  \\$aEdinburgh :$bThe Scottish Text Society,$c1996.
=300  \\$aix, 265 p. ;$c23 cm.
=490  \\$aScottish Text Society. ; Fourth series ; $v24
=500  \\$aNo music but there are references to relevant tunes, from Bronson
and other sources.
=650  \7$2UkLoVW$aFolk songs$9202
=650  \7$2UkLoVW$aScotland$9461
=700  \\$919389$aCrawfurd, Andrew$d1786-1854
=700  1\$91452$aLyle, Emily B.
=850  \\$aUkLoVW
=942  \\$2VWML$cBK$hMPS 60 (22)$n0$6MPS0060  (00022)
=999  \\$c16320$d16320
=952
 \\$00$10$2VWML$40$6MPS_00060_22$71$916978$aVWML$bVWML$d1998-01-01$l0$oMPS
60 (22)$p13972$r2012-10-31$w2012-10-31$yBK

=LDR  00966nam a22002651a 4500
=001  201508181250.nw
=003  UkLoVW
=005  20200809133340.0
=008  121030s1975\\\\stkag\\gr\\\\\000\0\eng\d
=020  \\$a1897976119
=040  \\$aUkLoVW$beng$cUkLoVW
=099  \\$aMPS 60 (22)
=245  10$aAndrew Crawfurd's collection of ballads and songs /$cedited by E.
B. Lyle.$bVolume 1
=260  \\$aEdinburgh :$bThe Scottish Text Society,$c1975.
=300  \\$alvii, 244 p. :$bill., music ;$c22 cm.
=490  \\$aScottish Text Society. ; Fourth series ; $v9
=588  \\$aCardbox (1998)
=650  \7$2UkLoVW$aFolk songs$9202
=650  \7$2UkLoVW$aScotland$9461
=700  \\$919389$aCrawfurd, Andrew$d1786-1854
=700  1\$91452$aLyle, Emily B.
=850  \\$aUkLoVW
=942  \\$2VWML$cBK$hMPS 60 (22)$n0$6MPS0060  (00022)
=999  \\$c66698$d66698
=952  \\$00$10$2VWML$40$6MPS0060
 (00022)$71$926287$aVWML$bVWML$d2015-08-18$l0$oMPS 60
(22)$p8052$r2015-08-18$w2015-08-18$yBK

Any help would be appreciated.
Thanks!
Elaine Bradtke
VWML <https://www.vwml.org>
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