This feature was spotted by user xxaarraa over on XDA Developers Forum, where the phone wouldn't juice up due to 'moisture detected in the charging port'.
We spoke to Samsung at MWC this year about this feature, and how it managed to offer the Galaxy S7 and S7 Edge without a cap to cover the charging port, in the same way Sony does to prevent this very problem.
"[Making a phone water resistant is] a great feature to have, but there are a lot of tradeoffs in making a sealed unit," said Kyle Brown, head of technology, content and launch management at Samsung.
"We coat it and seal on the inside rather than outside, and that's how it's capable to still have the connection for the charger, and not have to worry [about water]."
The issue with having exposed ports on a water-resistant phone is, obviously, that water can remain in the handset after it's been dunked – and if you add electricity into the mix, that can lead to terminal short circuiting.
However, the Galaxy S7 monitors the current coming from the port (which is used for other tasks, such as maintaining optimal charge from the wall) and will lock things down if anything untoward, like pesky H2O, is noted:
"The device will protect itself, so if it was to detect something wrong with the amount of current running to it, it wouldn't charge and will warn you," added Brown.
"[Water resistance] was a massive engineering challenge, to do it without a cap in the bottom is another great achievement."
Sony also spoke to techradar about the issues around making phones waterproof, highlighting the "risk" of offering phones resistant to water as people "may not use them in the proper way" and open the cap used on Sony's Xperia phones when in water, which could destroy the phone.
Phones that can be truly adaptive, offering failsafe mechanisms to protect us from our daily phone habits, should be the future – it's irritating if you have to wait to charge, but it's far better to do it that way than have a broken port on an expensive smartphone.