Plaid imitates major bank account UIs in their login forms to make users more comfortable submitting their bank credentials to Plaid. This issue was addressed in this Github issue (archived from WaybackMachine): http://web.archive.org/web/20190415103059/https://github.com/plaid/link/issues/68
The Github issue has since been deleted, as shown here: https://github.com/plaid/link/issues/68. I'm hoping this isn't a repost, but this behavior seems ridiculous to me, and I'm hoping to bring it to wider attention (if it isn't already).
Edit: post flagged for some reason. Oh well.