I've been experiencing this bug since MCPE patch 0.11.0 until now, The fishing rod's bobber appear black or there is no Texture/Skin rendered o that entity/thing.
On the newest iPad Mini's The Fishing Rod Bobber Appears Normal than the iPad Mini 1.
I know it's been already reported, BUT there is no sign that the Officials are Fixing it.
Thank you for your report! However, this issue was reported earlier as MCPE-8565. Please add a comment summarizing your experience there. Consider doing a search next time, to check if your issue doesn't exist already.