Silicone solution ?

I have used silicone for years to seal bathroom joints etc . Now I am not the fastest , but I can run a very smooth seal . I clean the joints throughly . Very lightly rub down with a light abrasive Scotchbrite. Wipe clean and then degrease with meths. I ensure that the silicone is well in date and a good brand , Screwfix's (?)
The joint below is a porcelain shower base to a small upvc panel . Outside the shower so is not getting wet . After a month or so lightly rubbing a finger over it has the effect in photo. It seems dry and not elastic like normal silicone . Second time I have made this joint with the same problem. I used a Mapei silicone , solvent based.
Any suggestions ? New silicone make ?
TIA

 

Strange. I used a branded sealant around the bath, no problems. ‘Unibond’, I think.

 

If FC's idea doesn't work I wonder if using grout first and then covering with sealant would make a difference.

 

Thanks all for the input. I will dump the current silicone I have . I was also having doubts about meths cleaning , although have used it for years . I have some isopropyl lens cleaner , so I will use that. I'll use the best ( most expensive ?) silicone I can get - Unibond from Screwfix at £9.99. I don't want to walk 1 mile around B and Q for one item . So I'll hold the CT1 in reserve.
I'll remake the joint this week - It's a bit of a pain removing all the old silicone and cleaning it. So lets hope this is the answer

 

Never seen silicone sealant go like that, it almost looks like it has hardened and then shrunk.
You say solvent based @HarryS , as far as I know there are two types, acetic cure (smells of vinegar) and neutral cure which is probably more used for glazing, but i've never seen either go like that.
The CT1 stuff is supposed to be the dogs small balls, but we only use it if the customer has allergies to the normal stuff.

 

Now the Geocel is an interesting sealant . Screwfix sell it . My joint is outside the shower and 100% dry so hopefully the Unibond sanitary sealant will do the job

 

Yes the one that smells like vinegar is the type I use . The solvent free is just being introduced.
The sealant has gone like plasticine in just over a month - never seen that before - must be a duff batch ?

 

Well I replaced my silicone yesterday. I cleared out all my old silicone from the garage . I found I had used a cheap silicone from a local DIY shop , I usually use a good Screwfix brand . Anyway it was easy cleaning the old silicone away it virtually rubbed off like plasticine ! A good cleaning with Scotchbrite and lens cleaner , then a 10mm fillet with Unibond - looks good .
I think the lesson is do not use cheap silicone