"However this is not always the case in" is correct and usable in written English. You can use this phrase when you want to introduce a contrast to a previous statement. For example: "Money can't buy happiness. However this is not always the case in relationships; having a partner with a steady income can bring a sense of security and stability.".
However, this is not always the case in rice paddy soil, and the underlying mechanisms are not well understood.
However, this is not always the case in the eyes of other members of the same team.
However, this is not always the case in 2017".
However, this is not always the case in the present study (Additional file 1: Table S4) and, in fact, cutoff values do not change much in general.
This is not always the case in clonally propagated plants.
Yet this was not always the case in this project.
However, this is not always the case for miRNAs in large-scale experiments (e.g. Morin et al., 2008).
When I feel like I can't trust my brain 100%, Ludwig really comes in handy. It makes me translate and proofread faster and my output more reliable.
Claudia Letizia
Head Translator and Proofreader @ organictranslations.eu