** Description
The caption "Caption 1" is not exported by ox-html in the following
source block.
#+caption: Caption 1
#+begin_src
foo bar baz
#+end_src
The begin_src block always requires a "language" as far as I know. If you don't want to specify a language, you can use #+begin_example instead.
You can even do "#+begin_src text".
It's a different issue as to why you are seeing a different behavior between the two exporters.