Hi. Nope, it shouldn’t be bad for SEO. The output is contained within your entry title’s H1 tag, and if you’d like to adjust it, you certainly can.
This is what I’ve written directly inside of the developer notes about SEO:
* 5. The reason that <spans> are being used is because HTML does not have a dedicated mechanism for
* marking up subheadings, alternative titles, or taglines. There are suggested alternatives from
* the World Wide Web Consortium (W3C); among them are spans, which work well for what we're trying
* to do with titles in WordPress. See the linked documentation for more information.
* @link https://www.w3.org/html/wg/drafts/html/master/common-idioms.html#sub-head
Hope that helps. See the W3C for more information.