Is this a new product, or is this something you've been making for a while but that has only just started to show problems with a recent batch / batches?
Useful to know as if it has worked consistently for some months then that demonstrates that your current formulation and processing regime is capable of achieving a stable end product in principle.
Mango is extremely pulpy and can present quite a challenge for stability!
If it has worked previously, how long have you been making it?
If nothing else has changed (water source etc) then changes in the fruit could be a potential source of issues. Presumably its still slightly too early to be getting puree from the 2019 crop, so this will be material that was processed last year using the 2018 crop?
How have you / your supplier stored the material prior to use, and have you noticed any changes in the physical character of the product?
Do you get the mango from more than one supplier/region, and is there any correlation between this and the appearance of problems in finished products?
Also, in terms of the sedimentation / phase separation, how is this appearing visually?
Is it a uniform smooth layer of pulp at the bottom, or does the pulp have a slightly lumpy appearance?
Sorry for all the questions, but over the years I've seen enough juice-based drinks doing strange things to be convinced that these types of issue can be quite simple or surprisingly complex!
Sometimes a small change in water can make a huge difference, sometimes a stabiliser will work most of the time but very occasionally you'll get a batch of fruit with slightly different chemistry and you'll potentially get precipitates/sediments forming, sometimes an unusual growing season will make an entire crop with unusual characteristics that means a recipe/process that was previously reliable will suddenly become unstable...