I know this is old but yes, it happens on every single SP31 v2.0
Thanks for answering that. I have two SP31 V2.0 and it does it on both so must be the way it was (probably unintentionally) designed. Luckily not a deal breaker for me.
I just got another SP31V2.0 which makes a total of 4 of these lights that I have purchased. With the latest one, it does not have that preflash on level 1, that I mentioned earlier. Maybe I got lucky with this one or maybe the newer ones Sofirn addressed it………….not sure.
You’re not the first one to report this.
However, Sofirn changed the threads in recent models. My SP31 V2.0 (sold) didn’t take the short SP40 18350 tube while newer models do.
Received one a couple of days ago. It’s perfect for EDC duty. Nice slim, pocketable size. Very bright and throwy. Simple UI. Really like the two button setup, and it can still tail stand.
Will probably give it to a lady friend who asked about a really good bright light she can easily use, and carry in a purse. Love Sofirn lights.
Just spotted this thread. My SP31V2.0, bought in November 2019, tail-stands without an issue... so guess they fixed that. I bought it as a stop-gap to replace a Fenix PD35 that stopped working, and was blown away by the quality and performance for the price. Just received the latest Fenix PD35V2.0 to review on Ireland's Wildlife, and see very little between the Sofirn SP31 and the much more expensive Fenix model in terms of build quality and performance.
And my SP31V2.0 tail-stands perfectly... while the Fenix doesn't 
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Which type of LED will recommend, XPL HI 6000K or LH351D 5000K?
The XP-L HI throws further, but has a weird yellow spot in the center of the beam, It’s not super noticable but once you do it’s annoying. I swapped in a 5700k LH351D and it doesn’t throw as far, but the beam is nicer.
So the XP-L HI if you want max throw, otherwise the LH351D.
Thank you, is there a noticeable difference between different types of light?