RuntimeError: the bucket being iterated changed size

[goschtl]

Hi

i get a problem when i try to query an DateTimeIndex with the help of zc.catalog.

My serachResults looks like this:

(modification_date=({'between': (datetime(2020, 11, 01), delete_datetime)}), type=('Unfallanzeige', 'Unfallanzeige'))

When i try to query i get this error...

File "/home/bghw/extranet/portal/eggs/zope.catalog-4.2.1-py2.7.egg/zope/catalog/catalog.py", line 135, in searchResults
results = self.apply(searchterms)
File "/home/bghw/extranet/portal/eggs/zope.catalog-4.2.1-py2.7.egg/zope/catalog/catalog.py", line 111, in apply
r = index.apply(index_query)
File "/home/bghw/extranet/portal/eggs/grokcore.catalog-3.0.1-py2.7.egg/grokcore/catalog/index.py", line 200, in apply
return super(_DatetimeIndex, self).apply(query)
File "/home/bghw/extranet/portal/eggs/zc.catalog-2.0.1-py2.7.egg/zc/catalog/index.py", line 241, in apply
values_to_documents.keys(*query))
File "/home/bghw/extranet/portal/eggs/zc.catalog-2.0.1-py2.7.egg/zc/catalog/index.py", line 240, in
[s for s in (values_to_documents.get(v) for v in
RuntimeError: the bucket being iterated changed size

Any idea what goes on ?

My Versions are:
zc.catalog-2.0.1
grokcore.catalog-3.0.1
zope.catalog-4.2.1

Thanks for your help
Christian