The workaround involves setting up a Text Replacement for the letter "i". To do this, go to Settings -> General -> Keyboard -> Text Replacement, and tap the plus (+) button. In the Phrase field, type an uppercase "I", and in the Shortcut field, type a lowercase "i". This should fix the problem until Apple addresses it properly in the next iOS update, which shouldn't be far off.
iPhone XS and XS Max in silver, space gray, and gold.