FWIW: There have, in the past but not recently that I remember, been reports of various Roku problems when there was an SD card installed. It does not really relate to any particular brand but Sandisk is reported more often by far than others.
I have noticed that people with large cards, 16 gb or larger mostly, have more problems than those that have a smaller card or no card at all. It should also be noted that no card larger than 4 gb (2 gb is usually plenty) will have its extra space used at all and the only thing that an SD card is used for is storing app code so that the apps do not need to be loaded from an online source. An SD card is NOT used for video storage or buffering or for app data storage or anything else in Roku operations except for storing app code for faster loading and if you do not have a fairly large number of apps you gain nothing from an SD card.
I never install an SD card as it would gain nothing for me. Also I have never seen the need for more than about 20-25 apps maximum. I only have 12 apps installed and I rarely use more than 6 of those in any month.
For those of you that have installed cards like 64 gb or 128 gb you are wasting that card in your Roku no matter how many apps you have installed.
But all that is pretty much off topic. My recommendation is that if you have any SD card in your Roku you seriously consider removing it unless you are absolutely sure that you are really gaining something from the card.