Wrong Counting Results

[Da...@coop.ch]

Hello Solr Team

I am a little bewildered about the counting capabilities of solr.
When I want to know how elements one would find for a given query, I set the limit to 0.
But setting the limit to 0 somehow leads to a wrong count. Sometimes I get a higher count that I would expect.

For example:

https://solr-wfr-develop-solr-wfr-develop-solrcloud.coop-gke-test2023.gcp.coop.ch/solr/workflow/select?indent=true&q.op=OR&q=task_coopProcessId%3A3020179&rows=0&start=0&useParams=

gives me:

responseHeader
zkConnected    true
status   0
QTime  24
params
q             "task_coopProcessId:3020179"
indent   "true"
start      "0"
q.op       "OR"
rows      "0"
useParams        ""
response
numFound         4
start      0
maxScore           1
numFoundExact             true
docs      []

So, one would expect 4 documents will be found with this query. But that is wrong, there are only 3 documents. What kind of problems lead to this weird behaviour?
This will be apparent when either setting the limit or the offset higher

https://solr-wfr-develop-solr-wfr-develop-solrcloud.coop-gke-test2023.gcp.coop.ch/solr/workflow/select?indent=true&q.op=OR&q=task_coopProcessId%3A3020179&rows=0&start=3&useParams=

responseHeader
zkConnected    true
status   0
QTime  6
params
q             "task_coopProcessId:3020179"
indent   "true"
start      "3"
q.op       "OR"
rows      "0"
useParams        ""
response
numFound         3
start      3
maxScore           1
numFoundExact             true
docs      []

This time its correct. But this particular offset only works for this query and is different for other queries.

With kind regards,

Dario Viva