Someone I knew was denied the opportunity to take a required citizenship test because they'd applied without their middle initial which appeared on their ID documents (or vice versa): a mismatch of "John Smith" vs "John Q Smith" was enough to cost them the test fee plus the day off work and travel to the test.
Similarly, https://www.theguardian.com/books/2018/aug/08/visas-refused-...
"According to Barley, the dozen authors were asked to provide three years’ worth of bank statements to demonstrate financial independence, despite being paid to participate in the Edinburgh book festival, and having publishers and the festival guaranteeing to cover their costs while in the UK. Barley said any deposits that could not be easily explained were used as grounds to deny the authors’ visas; one had to reapply three times due to her bank statements."
There definitely was a story which I can't find of someone being rejected because they didn't have enough money in their bank account, securing a transfer of money from a relative, re-applying and then being denied due to the "unexplained" transfer.