What 4give said about small batches and lemon juice.
I'm curious how you developed your recipes, what resources were you using? Any time I see lemon juice in primary, I think "ooh, that's an old recipe." Current methods don't recommend using lemon juice in primary because not only is the fruit acidic (rhubarb is for sure) and the honey acidic but the yeast will produce even more acidity and if the pH gets too low, you might start running into problems with stuck fermentations or stinky annoyed yeast. If the mead is a bit bland or flat, by all means add lemon juice after fermentation to balance things out, but though many successful batches (including a lot of my own) have been done with lemon juice, it's a way better habit to get into to use it after. And if you want that zing of citrus flavour, the zest is what you want anyways, the juice really doesn't have a lot of flavour.
Are you using any pectic enzyme? I typically mix my must, add the pectic enzyme, wait 24h, then check the SG and then pitch my yeast because the pectic enzyme can cause the fruit to release more of its sugars into the must, but then I tend to only use fruit in primary. Calculating the amount of sugar you add with secondary fruit additions gets tricky and you want your before and after volumes and your before and after specific gravities, then it's just a straight concentration calculation.
When you say "blended and squeezed", do you mean you ran it through a blender then strained out the bigger solids through something like a jelly bag or cheesecloth? Don't be afraid to be very descriptive when you're asking for help with troubleshooting, also when you say you add fruit in primary and secondary, that suggests that the amount of fruit you stated in your recipe might not all have been added, more words is more better when it comes to trying to share your work so others can check it over

And as 4give pointed out, those batches will be over 6 gallons if you included 5 gallons of water rather than water up to 5 gallons, which is how I usually do it (I measured it out on all my primary fermentation buckets and made sharpie marks on the outside so I just fill a bit past the line then when I rack, it's enough to fill the carboy after losing some to lees and fruit crud). I'm also not sure how you measured your SG, you didn't state whether you used a hydrometer or refractometer so I'm assuming you have a hydrometer.
In the future you might want to check the SG before adding fruit, then after, then you'll know for sure where your high readings are coming from, you didn't state whether you checked before adding the fruit. Though in my experience, straight fruit juice other than grape juice rarely exceeds about 1.060 so so you're more likely decreasing the SG by diluting the must, and any solids that make it into the must should not be affecting the spcific gravity, only dissolved sugars should.
We used to have a mead calculator around here that could give an approximation of what your SG should be based on your total volume and the amount of honey you add, but it's been a while and a couple site rearrangements since I've used it... aah there it is
https://gotmead.com/blog/the-mead-calculator/
It thinks your initial SG should be about 1.100 if you made aa 5 gal batch, less if you used the entire 5 gallons of water, so something's definitely weird. Did you test the fruit SG separately before adding it?
Things that could cause a false high reading could include the must being really cold (I don't think it would make it .05 too high though), the hydrometer being out of calibration, or air bubbles stuck to the hydrometer and making it float, I sometimes get fermentation bubbles doing that when I'm checking the progress after pitching so I make sure to give the hydrometer a spin (or if it's in a plastic hydrometer test container, I'll tap it to gently bounce it off the bottom) just before I read it to knock any bubbles off.
Have you tested your hydrometer? Make sure it gives you a reading of 1.000 when in room temperature water.
Good luck, and I hope you get to the bottom of this, something's definitely off somewhere.