I just tried your sample txt file in a txt-to-epub conversion. This is what the resulting epub's html file looked like, which looks correct to me:
Code:
<p class="calibre1">Paragraph 1.</p>
<blockquote class="calibre2">
<p class="calibre1">Blockquote line 1.</p>
<p class="calibre1">Blockquote line 2.</p>
</blockquote>
<p class="calibre1">Paragraph 2.</p>
I used the following setting :
Convert - TXT Input - Formatting style - markdown
There isn't really enough in the sample txt file to advise on the best setting for
Paragraph style on the same page, but
auto,
block or
single all worked for me.
BTW welcome to MobileRead